Buy reserved capacity
Sign in to the Azure portal.
Select All services > Reservations.
Select Add and then in the Purchase Reservations pane, select SQL Database to purchase a new reservation for SQL Database.
Fill in the required fields. Existing databases in SQL Database and SQL Managed Instance that match the attributes you select qualify to get the reserved capacity discount. The actual number of databases or managed instances that get the discount depends on the scope and quantity selected.

Review the cost of the capacity reservation in the Costs section.
Select Purchase.
Select View this Reservation to see the status of your purchase.
Reference:
https://docs.microsoft.com/en-us/azure/azure-sql/database/reserved-capacity-overview

With Cosmos DB's novel multi-region (multi-master) writes replication protocol, every region supports both writes and reads. The multi-region writes capability also enables:
Unlimited elastic write and read scalability.
99.999% read and write availability all around the world.
Guaranteed reads and writes served in less than 10 milliseconds at the 99th percentile.
Reference:
https://docs.microsoft.com/en-us/azure/cosmos-db/distribute-data-globally

B: To access a key vault during template deployment, set enabledForTemplateDeployment on the key vault to true.
D: The user who deploys the template must have the Microsoft.KeyVault/vaults/deploy/action permission for the scope of the resource group and key vault.
Incorrect Answers:
E: To grant access to a user to manage key vaults, you assign a predefined key vault Contributor role to the user at a specific scope.
If a user has Contributor permissions to a key vault management plane, the user can grant themselves access to the data plane by setting a Key Vault access policy. You should tightly control who has Contributor role access to your key vaults. Ensure that only authorized persons can access and manage your key vaults, keys, secrets, and certificates.
Reference:
https://docs.microsoft.com/en-us/azure/azure-resource-manager/templates/key-vault-parameter
https://docs.microsoft.com/en-us/azure/key-vault/general/overview-security

To prevent Data Loss, Premium/Business Critical is required:
The primary node constantly pushes changes to the secondary nodes in order and ensures that the data is persisted to at least one secondary replica before committing each transaction. This process guarantees that if the primary node crashes for any reason, there is always a fully synchronized node to fail over to.

Azure Stream Analytics is a fully managed stream processing engine that is designed to analyze and process large volumes of streaming data with low latency. Patterns and relationships can be identified in data that originates from various input sources including applications, devices, and sensors. You can use these patterns to trigger actions and initiate workflows such as creating alerts or feeding information to a reporting tool. Stream Analytics is also available on the Azure IoT Edge runtime, enabling data processing directly on the edge.
Reference:
https://learn.microsoft.com/en-us/azure/iot/iot-overview-analyze-visualize