When can a work vest be substituted for a lifejacket in the total count of the required lifesaving gear?

Correct Answer: Option B — A work vest may never be counted as a lifejacket.

Approved work vests provide ergonomic utility for crewmembers working near water but do not meet USCG standards for primary lifesaving appliances, meaning they may never substitute for an approved lifejacket in the required safety inventory.