Reference:
https://docs.microsoft.com/en-us/azure/azure-sql/database/logins-create-manage Basic Concept: This question tests identity and authentication for Azure SQL and SQL Server workloads, including when to use contained users, directory identities, certificate validation, or authentication profiles.
Why A is Correct: Create User1 in the master database. is a security-related control, but its value depends on whether the requirement is identity, encryption, auditing, network isolation, or data exposure reduction. In this scenario, the important constraint is: You need to ensure that when User1 connects to the logical server by using Azure Data Studio, User1 can see all the databases. Create User1 in the master database. satisfies that constraint without adding an unrelated service or manual process.
Why B is Wrong: Assign User1 the db_datareader role for the master database. is a security-related control, but its value depends on whether the requirement is identity, encryption, auditing, network isolation, or data exposure reduction. It protects or manages a different security layer, so the required database access or protection behavior would still be incomplete.
Why C is Wrong: Assign User1 the db_datareader role for the databases that Userl creates. is a security- related control, but its value depends on whether the requirement is identity, encryption, auditing, network isolation, or data exposure reduction. It is not the right enforcement point for this case; the scenario needs the control that governs the data or identity path being tested.
Why D is Wrong: Grant select on sys.databases to public in the master database. is a security-related control, but its value depends on whether the requirement is identity, encryption, auditing, network isolation, or data exposure reduction. It does not satisfy the required identity, encryption, firewall, auditing, or data-exposure boundary described in the scenario: You need to ensure that when User1 connects to the logical server by using Azure Data Studio, User1 can see all the databases.