to meet the requirement for the number of vdss on board what must be true about pyrotechnic vdss

Pyrotechnic VDSs must be at least three unexpired signals on board to satisfy the requirement. They also need to be Coast Guard-approved, in serviceable condition, and readily accessible.

If you want the exact test-style wording, the safest answer is:

• At least three pyrotechnic VDSs must be carried.
• They must be unexpired.
• They must be approved and usable.