Proper lubrication of the main bearing is more easily obtained in a single acting four-stroke/cycle diesel engine than in a single acting two-stroke/cycle diesel engine because （）

A. bearing pressure in a four-stroke\cycle acting single diesel engine is continually reversed
B. bearing pressure in a two-stroke\cycle single acting diesel engine is continually reversed
C. the maximum bearing pressure is higher in a single acting two-stroke/cycle diesel engine
D. two-stoke/cycle diesel engines require more complicated lubrication piping