A power-driven vessel shall have her engine ready for _________when the visibility is restricted.

A、A power-driven vessel shall have her engine ready for _________when the visibility is restricted.
B、A power-driven vessel shall have her engine ready for _________when the visibility is restricted.
C、A power-driven vessel shall have her engine ready for _________when the visibility is restricted.
D、A power-driven vessel shall have her engine ready for _________when the visibility is restricted.
E、A power-driven vessel shall have her engine ready for _________when the visibility is restricted.
F、A power-driven vessel shall have her engine ready for _________when the visibility is restricted.
G:A power-driven vessel shall have her engine ready for _________when the visibility is restricted.
H:A power-driven vessel shall have her engine ready for _________when the visibility is restricted.