【名词&注释】
螺旋桨(propeller)、柴油机(diesel engine)、船舶动力装置(marine power plant)、涡轮增压器(turbocharger)、二冲程低速
[单选题]Charging-air pressure increases if there is incorrect combustion and drop in the () of the diesel engine.
A. machine efficiency
B. machinery efficiency
C. mechanical efficiency
D. mechanics efficiency