Correct Answer:
B. Not an offence
An act committed by a person of unsound mind is not an offence under the Pakistan Penal Code (P.P.C.). Section 84 provides a general exception, stating that nothing is an offence if done by a person who, due to unsoundness of mind, is incapable of knowing the nature of the act, or that it is wrong or contrary to law. This principle is rooted in the legal requirement of mens rea (guilty mind) for criminal liability. Since a person of unsound mind lacks this capacity, their actions are excused. Therefore, stating it is "An offence" is incorrect, and it does not merely "Depends upon nature of the act" but fundamentally on the mental state of the perpetrator.