Final answer:
The proposed solution is incorrect; U1 should be added to the DatabaseMailUserRole in the msdb database, not the model database, in order to send mail using Database Mail, hence the answer is False.
Step-by-step explanation:
The solution of adding the DatabaseMailUserRole to the user U1 in the model database does not meet the goal of configuring a SQL Server instance to ensure that the user U1 can send mail using Database Mail. The model database serves as the template for all new databases created on the instance of SQL Server. However, database-level roles in the model database do not automatically apply to the msdb database, which is where Database Mail configuration is stored.
To correctly configure Database Mail, U1 needs to be added to the DatabaseMailUserRole in the msdb database, not the model database. This allows U1 to use Database Mail as per the required permissions. Therefore, the correct answer to the question is False.