If the flame from combustion in the cylinder of a four-stroke engine past the piston into the space below, the accumulation of flammable mixture would be ignited, thus resulting in （）.

A.low compression
B.failure of the fuel pump to discharge fuel
C.incorrect timing of fuel pump
D.turning gear being still on

A.failure of the fuel pumps
B.starting air pressure too low
C.stop valve in air line closed
D.the turning gear still engaged

A.low compression of the fuel pumps
B.incorrect timing of fuel pumps
C.the starting air valves stuck
D.air-locks in fuel oil pipeline