The answer is: C
Explanation
The correct option is C: Wilful wrong or Fraud.
A sub-agent is a person who is appointed by an agent to perform some act or represent the principal in dealings with third persons. A sub-agent is properly appointed when the agent has the authority to do so, either by the express or implied consent of the principal, or by the custom of the trade.
When a sub-agent is properly appointed, the principal is bound by and responsible for his acts, as if he were an agent originally appointed by the principal. However, the principal is not responsible for the acts of a sub-agent who is appointed without authority, unless he ratifies them.
Therefore, a sub-agent is responsible to the principal on the grounds of wilful wrong or fraud, which are intentional acts that cause harm or loss to the principal. Wilful wrong means a deliberate breach of duty or violation of law by the sub-agent. Fraud means a dishonest or deceitful act by the sub-agent to deceive or cheat the principal or a third person.
For example, if A appoints B as his agent to sell his goods, and B appoints C as a sub-agent to do the same, with A's consent, then A is responsible for C's acts as if C were his agent. However, if C sells the goods at a lower price than instructed by A, and keeps the difference for himself, then C is guilty of wilful wrong and fraud, and is responsible to A for the loss.