Can a 1985 and 1986 option agreement be invalid and unenforceable?

In order for the 1985 and 1986 agreements to be invalid and unenforceable, they would have had to be merged in the option agreement. In determining whether the contract had been superseded by another contract, the intentions of the parties must be determined by looking at the terms of the contract and the surrounding circumstances. In Morris v. Baron and Co., [1918] A.C. 1 at p. 19, Lord Haldane dealt with merger as follows: "... What is, of course, essential is that there should have been made manifest the intention in any event of a complete extinction of the first and formal contract, and not merely the desire of an alteration, however sweeping, in terms which still leave it subsisting."