Explanation/Reference:
Explanation:
The performance issues is related to locking.
B: sp_lock reports snapshot information about locks, including the object ID, index ID, type of lock, and type or resource to which the lock applies.
D: The Activity Monitor in SQL Server Management Studio is useful for ad hoc views of current activity and graphically displays information about:
Processes running on an instance of SQL Server.

Blocked processes.

Locks.

User activity.

Incorrect Answers:
E: System Monitor primarily tracks resource usage, such as the number of buffer manager page requests in use, enabling you to monitor server performance and activity using predefined objects and counters or user-defined counters to monitor events. System Monitor (Performance Monitor in Microsoft Windows NT
4.0) collects counts and rates rather than data about the events (for example, memory usage, number of active transactions, number of blocked locks, or CPU activity). You can set thresholds on specific counters to generate alerts that notify operator References: https://docs.microsoft.com/en-us/sql/relational-databases/performance/performance- monitoring-and-tuning-tools?view=sql-server-2017