When both the database management system and client are under the same ownership (e.g. when SQL Server is deployed to a virtual machine), transactions are available and the lock duration can be controlled. Reference:
https://docs.particular.net/nservicebus/azure/understanding-transactionality-in-azure

Explanation:
Front Door: Protection against Open Web Application Security Project (OWASP) vulnerabilities1 API Management: IP filtering on a per-API level2 and validation of Azure B2C JSON Web Tokens (JWTs)3 References:
1: Azure Front Door - Web Application Firewall 2: Azure API Management policy reference - ip-filter 3: How to validate an Azure B2C JWT token in a web API?

General Purpose / Standard prevents data loss through high available storage https://docs.microsoft.com/en-us/azure/azure-sql/database/service-tier-general-purpose?view=azuresql. This architectural model relies on high availability and reliability of Azure Blob storage that transparently replicates database files and guarantees no data loss if underlying infrastructure failure happens. General Purpose / Standard support Zone Redundancy For General Purpose tier the zone-redundant configuration is Generally Available in the following regions: https://docs.microsoft.com/en-us/azure/azure-sql/database/high-availability-sla?view=azuresql&tabs=azure-powershell Without any information regarding the usage pattern, serverless is possible. Other option is D https://docs.microsoft.com/en-us/azure/azure-sql/database/serverless-tier-overview?view=azuresql

Explanation
Directory synchronization between Azure Active Directory (Azure AD) and corp.fabrikam.com must not be affected by a link failure between Azure and the on-premises network. (This requires domain controllers in Azure) Users on the on-premises network must be able to authenticate to corp.fabrikam.com if an Internet link fails.
(This requires domain controllers on-premises)
Topic 3, Contoso
Case Study
This is a case study. Case studies are not timed separately. You can use as much exam time as you would like to complete each case. However, there may be additional case studies and sections on this exam. You must manage your time to ensure that you are able to complete all questions included on this exam in the time provided.
To answer the questions included in a case study, you will need to reference information that is provided in the case study. Case studies might contain exhibits and other resources that provide more information about the scenario that is described in the case study. Each question is independent of the other questions in this case study.
At the end of this case study, a review screen will appear. This screen allows you to review your answers and to make changes before you move to the next section of the exam. After you begin a new section, you cannot return to this section.
To start the case study
To display the first question in this case study, click the button. Use the buttons in the left pane to explore the content of the case study before you answer the questions. Clicking these buttons displays information such as business requirements, existing environment, and problem statements. If the case study has an All Information tab, note that the information displayed is identical to the information displayed on the subsequent tabs. When you are ready to answer a question, click the button to return to the question.
Existing Environment: Technical Environment
The on-premises network contains a single Active Directory domain named contoso.com.
Contoso has a single Azure subscription.
Existing Environment: Business Partnerships
Contoso has a business partnership with Fabrikam, Inc. Fabrikam users access some Contoso applications over the internet by using Azure Active Directory (Azure AD) guest accounts.
Requirements: Planned Changes
Contoso plans to deploy two applications named App1 and App2 to Azure.
Requirements: App1
App1 will be a Python web app hosted in Azure App Service that requires a Linux runtime. Users from Contoso and Fabrikam will access App1.
App1 will access several services that require third-party credentials and access strings. The credentials and access strings are stored in Azure Key Vault.
App1 will have six instances: three in the East US Azure region and three in the West Europe Azure region.
App1 has the following data requirements:
* Each instance will write data to a data store in the same availability zone as the instance.
* Data written by any App1 instance must be visible to all App1 instances.
App1 will only be accessible from the internet. App1 has the following connection requirements:
* Connections to App1 must pass through a web application firewall (WAF).
* Connections to App1 must be active-active load balanced between instances.
* All connections to App1 from North America must be directed to the East US region. All other connections must be directed to the West Europe region.
Every hour, you will run a maintenance task by invoking a PowerShell script that copies files from all the App1 instances. The PowerShell script will run from a central location.
Requirements: App2
App2 will be a NET app hosted in App Service that requires a Windows runtime. App2 has the following file storage requirements:
* Save files to an Azure Storage account.
* Replicate files to an on-premises location.
* Ensure that on-premises clients can read the files over the LAN by using the SMB protocol.
You need to monitor App2 to analyze how long it takes to perform different transactions within the application. The solution must not require changes to the application code.
Application Development Requirements
Application developers will constantly develop new versions of App1 and App2. The development process must meet the following requirements:
* A staging instance of a new application version must be deployed to the application host before the new version is used in production.
* After testing the new version, the staging version of the application will replace the production version.
* The switch to the new application version from staging to production must occur without any downtime of the application.
Identity Requirements
Contoso identifies the following requirements for managing Fabrikam access to resources:
* Every month, an account manager at Fabrikam must review which Fabrikam users have access permissions to App1. Accounts that no longer need permissions must be removed as guests.
* The solution must minimize development effort.
Security Requirement
All secrets used by Azure services must be stored in Azure Key Vault.
Services that require credentials must have the credentials tied to the service instance. The credentials must NOT be shared between services.

Explanation
Immutable storage for Azure Blob storage enables users to store business-critical data objects in a WORM (Write Once, Read Many) state.
Immutable storage supports:
Time-based retention policy support: Users can set policies to store data for a specified interval. When a time-based retention policy is set, blobs can be created and read, but not modified or deleted. After the retention period has expired, blobs can be deleted but not overwritten.
Reference:
https://docs.microsoft.com/en-us/azure/storage/blobs/storage-blob-immutable-storage