6. A vessel is moored with both anchors leading ahead on open moor. What is the open angle of both chains while the stress of each cable equal to the stress of vessel lying to a single anchor dead ahead?
(A) 90 degrees.
(B) 100 degrees.
(C) 120 degrees.
(D) 135 degrees.

一艘船繫泊在開放式繫泊區，兩個錨均在船首...