Scenario: Litware must meet technical requirements including:
Ensure that VM3 can establish outbound connections over TCP port 8080 to the applications servers in the Montreal office.
IP flow verify checks if a packet is allowed or denied to or from a virtual machine. The information consists of direction, protocol, local IP, remote IP, local port, and remote port. If the packet is denied by a security group, the name of the rule that denied the packet is returned. While any source or destination IP can be chosen, IP flow verify helps administrators quickly diagnose connectivity issues from or to the internet and from or to the on-premises environment.
Reference:
https://docs.microsoft.com/en-us/azure/network-watcher/network-watcher-ip-flow-verify-overview
Topic 3, Contoso Ltd
Existing Environment
Currently, Contoso uses multiple types of servers for business operations, including the following:
File servers
Domain controllers
Microsoft SQL Server servers
Your network contains an Active Directory forest named contoso.com. All servers and client computers are joined to Active Directory.
You have a public-facing application named App1. App1 is comprised of the following three tiers:
A SQL database
A web front end
A processing middle tier
Each tier is comprised of five virtual machines. Users access the web front end by using HTTPS only.
Requirements
Planned Changes
Contoso plans to implement the following changes to the infrastructure:
Move all the tiers of App1 to Azure.
Move the existing product blueprint files to Azure Blob storage.
Create a hybrid directory to support an upcoming Microsoft Office 365 migration project.
Technical Requirements
Contoso must meet the following technical requirements:
Move all the virtual machines for App1 to Azure.
Minimize the number of open ports between the App1 tiers.
Ensure that all the virtual machines for App1 are protected by backups.
Copy the blueprint files to Azure over the Internet.
Ensure that the blueprint files are stored in the archive storage tier.
Ensure that partner access to the blueprint files is secured and temporary.
Prevent user passwords or hashes of passwords from being stored in Azure.
Use unmanaged standard storage for the hard disks of the virtual machines.
Ensure that when users join devices to Azure Active Directory (Azure AD), the users use a mobile phone to verify their identity.
Minimize administrative effort whenever possible.
User Requirements
Contoso identifies the following requirements for users:
Ensure that only users who are part of a group named Pilot can join devices to Azure AD.
Designate a new user named Admin1 as the service administrator of the Azure subscription.
Admin1 must receive email alerts regarding service outages.
Ensure that a new user named User3 can create network objects for the Azure subscription.

To port forward traffic to a specific port on specific VMs use an inbound network address translation (NAT) rule.
https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-overview an inbound NAT rule :
Create a load balancer inbound network address translation (NAT) rule to forward traffic from a specific port of the front-end IP address to a specific port of a back-end VM.
Hence this option is Correct
a load balancing rule : Incorrect Choice
A load balancer rule defines how traffic is distributed to the VMs. The rule defines the front-end IP configuration for incoming traffic, the back-end IP pool to receive the traffic, and the required source and destination ports.
a new public load balancer for VM3 : Incorrect Choice
This option will not help you since this will route all traffic to VM3 only.
a frontend IP configuration : Incorrect Choice
When you define an Azure Load Balancer, a frontend and a backend pool configuration are connected with rules. The health probe referenced by the rule is used to determine how new flows are sent to a node in the backend pool. The frontend (aka VIP) is defined by a 3-tuple comprised of an IP address (public or internal), a transport protocol (UDP or TCP), and a port number from the load balancing rule. The backend pool is a collection of Virtual Machine IP configurations (part of the NIC resource) which reference the Load Balancer backend pool.
Reference:
https://docs.microsoft.com/en-us/azure/load-balancer/tutorial-load-balancer-port-forwarding-portal
https://pixelrobots.co.uk/2017/08/azure-load-balancer-for-rds/

Cost analysis: Correct Option
In cost analysis blade of Azure, you can see all the detail for custom time span. You can use this to determine expenditure of last few day, weeks, and month. Below options are available in Cost analysis blade for filtering information by time span: last 7 days, last 30 days, and custom date range. Choosing the first option (last 7 days) auditors can view the costs by time span.
Cost analysis shows data for the current month by default. Use the date selector to switch to common date ranges quickly. Examples include the last seven days, the last month, the current year, or a custom date range. Pay-as-you-go subscriptions also include date ranges based on your billing period, which isn't bound to the calendar month, like the current billing period or last invoice. Use the <PREVIOUS and NEXT> links at the top of the menu to jump to the previous or next period, respectively. For example, <PREVIOUS will switch from the Last 7 days to 8-14 days ago or 15-21 days ago.

Invoice: Incorrect Option
Invoices can only be used for past billing periods not for current billing period, i.e. if your requirement is to know the last week's cost then that also not filled by invoices because Azure generates invoice at the end of the month. Even though Invoices have custom timespan, but when you put in dates for a week, the pane would be empty. Below is from Microsoft document:

Resource Provider: Incorrect Option
When deploying resources, you frequently need to retrieve information about the resource providers and types. For example, if you want to store keys and secrets, you work with the Microsoft.KeyVault resource provider. This resource provider offers a resource type called vaults for creating the key vault. This is not useful for reviewing all Azure costs from the past week which is required for audit.
Payment method: Incorrect Option
Payment methods is not useful for reviewing all Azure costs from the past week which is required for audit.
Reference:
https://docs.microsoft.com/en-us/azure/cost-management-billing/costs/quick-acm-cost-analysis
https://docs.microsoft.com/en-us/azure/cost-management-billing/manage/download-azure-invoice-daily-usage-date