单项选择题
A.are tracked on reciprocal bearings B.are tracked at the same range C.are tracked on the same bearing D.pass close together
A.give better range performance in rain，hail，etc B.display small targets in a mass of dense sea clutter at a greater range C.have less sea return in choppy rough seas D.display a more map like presentation for inshore navigation
A.be more suitable for river and harbor navigation B.provide better range performance on low lying targets during good weather and calm seas C.have a wider horizontal beam width D.have more sea return during rough sea conditions