In a four stroke cycle diesel engine, the inlet valve

A)
opens at 20° before top dead centre and closes at 40° after bottom dead centre
B)
may open and close anywhere
C)
opens at top dead centre and closes at bottom dead centre
D)
opens at 20° after top dead centre and closes at 20° before bottom dead centre

Correct Answer : Option (A) :   opens at 20° before top dead centre and closes at 40° after bottom dead centre