Look!The bus----- at a small bus stop.( ) A.stop B.is stoppi

Look!The bus_____ at a small bus stop.( ) A.stop B.is stopping C.stopping D.stops
LOOK后面跟V-ing形式,选B,可有人说stop是瞬间完成的动作,不用进行时.The bus是第三人称单数,故选D.请问到底选哪一个?