Answer:In this case the buyer is not bound by the contract because "this contract may not be assigned" means that duties may not be delegated, and the seller delegated a duty.
Here, the agreement is particularly defined by a provision that clearly states that: “This contract may not be assigned, and any violation of this prohibition voids the contract.” Therefore, if after the contract is signed and thus the production of the commodity is overtaken by another manufacturer , then the buyer's claim is right and he is not bound by the contract.
Therefore, the correct option is (A).