Simon has signed a contract with Miley agreeing to provide her company with 1,000 frozen pizzas each week. The contract states: “This agreement can only be modified by a written instrument signed by the party to be charged with such amendment.” But when Simon and Miley run into each other on the train, they agree that he will provide 750 pizzas instead. Which of the following statements is true?

(a) As long as they both agree, they can amend the contract orally. They do not have to sign anything.

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(b) For the change to be valid, both parties must sign an amendment because both parties are affected by it.

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(c) Only Miley has to sign the amendment because she is the one to be charged by it.

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(d) Only Simon must sign the amendment because he is the one to be charged by it.