The legal principle states that nothing is an offense if it is done in the exercise of the right of private defense. This principle allows individuals to use necessary force to defend themselves or their property from imminent harm or danger.

In the given factual situation, Anand and his friends reached Sham's house and abused him. Sham, in response, threw boiling water over Anand's face, resulting in burn injuries. In this situation, Sham may be able to use the defense of private defense to avoid criminal liability for his actions.

However, the defense of private defense has certain limitations. The force used in self-defense must be proportionate to the harm or danger faced. It cannot exceed the reasonable limits necessary to defend oneself or one's property. Therefore, the facts of the case would need to be examined to determine if Sham's actions were reasonable and proportionate to the harm faced.

Option C is the correct decision, as Sham acted in self-defense, and therefore, did not commit any offense. Anand's actions before the boiling water was thrown may also be considered in determining whether he committed an offense. However, the information provided in the factual situation is insufficient to make a determination about Anand's guilt or innocence.