单项选择题
A towing light，according to the Rules，is a（）.
A.white light B.red light C.yellow light D.blue light
单项选择题 A towing light is a yellow light having the same characteristics as a(n)（）
单项选择题 A single towing light will be carried above a vessel’s sternlight（）.
单项选择题 A safe water daymark has what shape? （）
