Explanation:

The question involves two applications - App1 and App2 - that both need read access to blobs in an Azure Storage account (storage1). Both apps are running in Azure container instances and use managed identities for authentication.
Let's analyze the requirements and correct configuration for each app based on Azure's security and access control models.
App1 - Minimize Secrets
App1 uses a managed identity, meaning it can be authenticated to Azure services without any stored credentials or secrets.
The best practice is to assign Azure RBAC permissions (role-based access control) directly at the storage account or container level.
By using Access control (IAM), you can assign the Storage Blob Data Reader role to App1's managed identity.
This method uses Azure AD-based authentication, requires no SAS tokens or access keys, and minimizes secret management.
Access is continuous until the role is removed or modified.
# Therefore, App1 # Access control (IAM)
App2 - Temporary 30-day Access
The requirement specifies that App2 should be able to read blobs only for 30 days.
Azure RBAC roles (IAM) do not provide time-bound permissions.
The appropriate way to grant time-limited access is through a Shared Access Signature (SAS).
A SAS token defines permissions, resource scope (e.g., container or blob), and an expiry time - making it ideal for temporary or limited access scenarios.
You can generate a SAS token valid for 30 days and assign it to App2.
# Therefore, App2 # Shared access signatures (SAS)
Why Not Access Keys or Advanced Security
Access Keys: Grant full control (read/write/delete) to the storage account - not secure or granular, and they cannot be time-bound.
Advanced Security: Refers to configurations such as firewall rules or encryption; not directly related to granting app access.
# Microsoft Azure Administrator Documentation Extract (AZ-104 Study Guide Reference):
"To enable secure access for applications, use Azure AD authentication with managed identities and assign appropriate RBAC roles via Access control (IAM). For temporary or limited access, use Shared Access Signatures (SAS) to specify permissions and expiry times." (Source: Microsoft Learn - Secure access to Azure Storage with Azure AD, SAS, and managed identities.)
# Final Verified Answer:
App1: Access control (IAM)
App2: Shared access signatures (SAS)