Mr. X who is usually of sound mind, but occasionally of unsound mind enters into a contract with Mr. Y when he is of unsound mind. Y came to know about this fact afterwards and now wants to file a suit against Mr. X.
X can never enter into a contract.
X can enter into the contract but burden is on other party to prove that he was of unsound mind at the time of contract.
X can enter into the contract but burden is on Mr X to prove that he was of unsound mind at the time of contract.
None of the above.
In this type of cases burden of proof usually lies with the person who claims to be of unsound mind. hence option c is correct.