You inherit a SQL Server 2022 instance hosting a critical financial database. A single backup file on a network share was created by a third-party script, and it contains multiple appended backup sets (full, differential, and log backups) written with WITH APPEND over several days. Before restoring, you must determine which backup set position in the file is the most recent full backup so you can build a correct restore sequence. Which T-SQL command should you run first to obtain this information?