P, with the intention of committing theft entered the house of Q. Q. on seeing him entering, struck him with a lathi and P fell down unconscious. Thereafter, Q gave him another blow of lathi at his head which caused his death. On being prosecuted for murder, Q took the plea of private defence. Which of the following argument is valid?

A. Since Q was acting in the exercise of right of private defence of his property, he had taken a valid defence

B. Since in the defence of one's property one cannot cause death of the intruder, Q has no defence

C. Q has used excessive force as once P fell unconscious; there was no need for the second blow. Hence, Q's plea of right of private defence will not succeed

D. If P committed house breaking in the night, Q has the right to cause death in the defence of his property, and thus Q's plea should prevail

Answer: Option C