The correct answer is D. voidable at the option of the party.
A contract is an agreement between two or more parties that creates an obligation to do or not do something. A contract is valid if it is made by parties who have the capacity to contract, for a lawful purpose, and with the necessary intent.
Coercion is the use of threats or force to make someone do something they do not want to do. Fraud is the intentional misrepresentation of a material fact in order to deceive another person. Misrepresentation is a false statement of fact made by one party to another, which has the effect of inducing that party into a contract.
If consent to an agreement is caused by coercion, fraud or misrepresentation, the agreement is voidable at the option of the party whose consent was so caused. This means that the party can choose to either enforce the contract or to void it.
Option A is incorrect because a contract that is voidable at the option of one party is not valid. Option B is incorrect because a contract that is voidable at the option of one party is not void ab initio. Option C is incorrect because a contract that is voidable at the option of one party is not legally enforceable.