You are signing on a crew. Which person is presenting a Merchant Mariner's Document (MMD) that you should suspect as being invalid?

Correct Answer: Option A — A seaman with an MMD only endorsed as "Bosun"

A Merchant Mariner's Document (MMD) must clearly state the specific rating or capacity for which the mariner is qualified. An endorsement simply stating 'Bosun' is insufficient, as 'Bosun' is a position or rank, not a formal rating endorsement recognized under 46 CFR Part 12 for legal certification of a mariner's competency.