The（）has a built-in world map; most areas are displayed on a scale of 4000 nm from the top to the bottom of the screen，and can be zoomed in to 150 nm.

A.all fishing vessels over 39 feet in length
B.sail-propelled fishing vessels
C.all fishing vessels of less than 200 GT
D.wooden hull fishing vessels with a poor radar echo

A.a plan-position indicator system
B.pulse-plan integration
C.pulse-pulse input
D.power-plan input

A.one target
B.two targets
C.three targets
D.a large number of targets