In dense fog a vessel without operational radar may not be justified（）at all but should anchor if it is safe and practicable for her to do so.

A.the state of visibility
B.the power of the vessel
C.the traffic density
D.the maneuverability of the vessel

A.the presence of the background light at night
B.the state of wind，sea and current
C.the number of crew on board
D.the draught in relation to the available depth of water

A.the characteristics，efficiency and limitation of the radar equipment
B.any constraints imposed by the radar range scale in use
C.the effect on radar detection of the sea state，weather and other sources of interference
D.the safe working load of the cranes both on board and ashore