A Struck B on the Head a Simple Blow with a Piece

Multiple Choice

A struck B on the head a simple blow with a piece of firewood B fell down bleeding from nose and become senseless. A and his wife thought that B was dead hence they placed B on the wooden pyre and set fire to it which caused B's death. A and his wife are guilty of

A) Simple hurt.
B) Murder.
C) Grievous hurt.
D) None of the above.