P Was Picked Up by a Gang of Robbers in a Car

Multiple Choice

P was picked up by a gang of robbers in a car from the street. He was given a revolver and asked to shoot at M. When P resisted, a revolver was put on his ear and he was told that if he did not shoot, he would be shot dead. Then P shot M dead. On a charge of murder, P argued that his act was not voluntary nor was there mens rea. P is guilty of:

A) Culpable homicide not amounting to murder.
B) No offence
C) Attempt to commit murder
D) Murder.