The correct option is A void
Section 21 of the Indian Contract Act, 1872 states that where a mistake in a contract relates to a foreign law, such a mistake is treated as mistake of fact. In furtherance of this, Section 20 states that where a contract has been entered into under a mistake of fact, the contract is void. The case of mistake of foreign law is an exception to the mistake of law or the maxim ignorantia juris neminem excusat (ignorance of law is no excuse).