The answer is: C
Explanation
The correct option is C: Undue influence.
The statement is based on the case of Earl of Aylesford v Morris, where the court held that a solicitor who sold a property to his client at an overvalued price had exercised undue influence over him. The court considered the relationship between the parties, which was one of trust and confidence, and found that the solicitor had abused his position to obtain an unfair advantage. The court also noted that the client did not have independent advice or full information before entering into the contract. Therefore, the contract was voidable at the option of the client.
Undue influence is a doctrine in contract law that refers to situations where one party exerts improper pressure or influence on another party to induce them into entering a contract against their will. Undue influence can arise in any relationship where one party has a dominant or fiduciary position over the other, such as solicitor-client, doctor-patient, parent-child, etc. The effect of undue influence is to make the contract voidable by the aggrieved party, who can rescind the contract and claim damages.