Final answer:
When Crew Trac shows 'DTY', the Flight Duty clock is running, as this indicates that the crew member is on active duty performing their assigned tasks. So, the best answer is a, yes.
Step-by-step explanation:
If Crew Trac, which is a software system used by airlines to manage crew scheduling, shows a status code of 'DTY', this typically indicates that the crew member is on duty.
Therefore, when Crew Trac displays 'DTY', the Flight Duty clock is indeed running.
This status reflects that a crew member has started their duty period, which includes all activities the crew must perform as part of their assignment, such as pre-flight planning, the flight itself, post-flight duties, and any standby or reserve time if applicable.
So, the best answer is a, yes.