单项选择题
A rigid replica of the International Code flag “A” may be shown by a vessel （）.
A.pulling a submarine cable B.engaged in diving operations C.engaged in underway replenishment D.transferring explosives
单项选择题 A report of casualty to a mobile offshore drilling unit must include （）.
单项选择题 A report of casualty to a mobile offshore drilling unit must be made in writing to which office? （）
单项选择题 A red triangular daymark marks （）.
