Question

Scenario: John, a businessman, entered into a contract with James regarding the sale of a piece of land. The contract specified the terms and conditions, including the agreed-upon price and payment schedule. However, John claims that he is not bound by the terms of the contract because he was not aware of the specific provision that required him to make an additional payment for the transfer of ownership.

Question: Determine whether John can claim ignorance of the fact as a defense to escape his obligation under the contract, citing relevant provisions of the Civil Code.