Under the U.S. Aids to Navigation System, a special mark possesses which of the following characteristics?

Correct Answer: Option B — May show a yellow light with a flashing rhythm

Special marks are used to indicate areas of interest, such as spoil grounds or traffic separation schemes. Under the U.S. Aids to Navigation System, these marks are yellow and, if lighted, must display a yellow light with a flashing rhythm, distinguishing them from lateral or cardinal aids.