Step 1: Understanding the Question:
The question asks for the definition of an agreement that can be enforced or rejected at the option of one party, but cannot be avoided by the other party.
Step 2: Key Legal Principles and Approach:
The interpretation clause, Section 2 of the Indian Contract Act, 1872, defines this concept under subsection (i).
Step 3: Detailed Explanation:
• Statutory Definition: Section 2(i) of the Act states: "An agreement which is enforceable by law at the option of one or more of the parties thereto, but not at the option of the other or others, is a voidable contract."
• Factors causing Voidability: A contract typically becomes voidable when the consent of one of the parties is not free.
• Under Section 19 and 19A, if consent to an agreement is caused by coercion, undue influence, fraud, or misrepresentation, the agreement is a contract voidable at the option of the party whose consent was so caused.
• Legal Status: Such a contract remains valid and fully binding on both parties until it is formally rescinded or avoided by the aggrieved party.
• If the aggrieved party chooses to validate it, the other party must perform their obligation.
• Therefore, Option (B) is the exact statutory term.
Step 4: Final Answer:
An agreement enforceable at the option of only one party is a voidable contract as per Section 2(i), making Option (B) the correct answer.