Choice "C" is correct. Duress through physical harm or the threat of physical harm renders a contract void rather than merely voidable.Choice "a" is incorrect. Mutual mistake renders a contract voidable by either party, rather than void.Choice "d" is incorrect. Use of undue influence renders a contract voidable at the option of the party influenced.Choice "b" is incorrect. Duress through improper threats is too broad to be correct. If the improper threats regard social or economic disadvantage, the contract is merely voidable. If the threats involve physical violence, then the contract is void.
