当船舶停靠码头时,为了保证船货安全,有必要24小时值班。（）

AWhen a vessel is alongside the wharf, it’s necessary for the ship to keep a 24-hour deck watch to guarantee the safety of the ship and the cargo.

BWhen a vessel is alongside the wharf, t’s necessary for the ship to keep a 24-hour gangway watch to guarantee the safety of the ship and the cargo.

CWhen a vessel is alongside the port, it’s necessary for the ship to keep a 24-hour deck watch to guarantee the safety of the ship and the cargo.

DWhen a vessel is alongside the port, it’s necessary for the ship to keep a 24-hour gangway watch to guarantee the safety of the ship and the cargo.