A. They work four hours and have four hours for rest.
B. They work eight hours and have four hours for rest.
C. They work four hours and have eight hours for rest.
D. They work eight hours and have eight hours for rest.

A. Sailors are always on watch on the bridge.
B. Deck officers are always on watch on the bridge.
C. Sailors are never on watch on the bridge.
D. Deck officers are never on watch on the bridge.