The Thai Government Begins a Tendering Process for Concessions to Search

The Thai government begins a tendering process for concessions to search for oil or gas deposits. A promising location between the Thai-Malaysian border is described as: 'In Thai waters, 1 mile offshore from the mouth of the Golok River'. United Petroleum Co (UP) tender successfully for the concession and embark on a costly undertaking to find oil reserves. After six months, the work is brought to a halt by the Malaysian government, who cite a border dispute that is pending at the International Court of Justice. The Thai government made no mention of this to UP, believing the area to fall within its territory. The successful exploitation of the site would have generated high revenues for UP and has only left them with enormous costs. What should UP argue before the courts in order to recoup its investments from the Thai government?

A) That the contract is void for common mistake at common law.
B) That the contract is voidable for common mistake in equity and should be set aside on terms.
C) That the Thai government (a) assumes the risk for this mistake, and so is in breach of contract, or (b) has induced UP's agreement by misrepresentation.
D) That the mistake was a mistake of law and therefore cannot void the contract.