Mark Owns a Cattle Station near Darwin

Mark owns a cattle station near Darwin. Mark is currently producing beef at an output level where marginal revenue exceeds marginal cost. In order to maximise his profit, Mark should

A) decrease his output.
B) shut down his cattle station.
C) increase his output.
D) not change his output.
E) probably change his output, but more information is needed to determine if he should increase, decrease or not change it.