A Sales Representative Knowingly Entered into a Contract for an Alarm

A sales representative knowingly entered into a contract for an alarm system during a door-to-door sales campaign with an obviously mentally ill individual.Why could the contract be immediately rendered voidable at that individual customer's request?

A) The contract is contrary to the culpable silence provisions contained in the Vulnerable Persons Act.
B) The contract is unenforceable in accordance with the Unconscionable Transactions Relief Act.
C) Establishing true consent is not possible due to the individual's incapacity to grasp the essence and effect of the contract.
D) The individual is lacking legal capacity and is unable to perform the contract in whole or in part.