cylinder walls being too hot

overheated spark plug points

red hot carbon deposits on cylinder walls

any one of these

starts at 15 Degree before top dead centre and ends at 30 Degree after top dead centre

starts at top dead centre and ends at 30? after top dead centre

starts at 15 Degree after top dead centre and ends at 30 Degree before bottom dead centre

may start and end anywhere

to reduce mass of the engine per brake power

to reduce space occupied by the engine

to increase the power output of an engine when greater power is required

all ofthe above

Correct

Incorrect

30 Degree before top dead center

30 Degree after top dead center

30 Degree before bottom dead center

30 Degree after bottom dead center