Which statement about a bilateral contract is true?

• A. It is always in writing.
• B. It requires an equal promise to perform.
• C. It lacks consideration.
• D. It is unenforceable if terms change.

Answer: (B)

In a bilateral contract, both parties exchange promises to perform. That reciprocal promise structure is what creates the binding agreement: each side commits to act in the future in return for the other side’s promise to act. The key point isn’t that the promises must be identical in value, but that there are promises on both sides—that each party has given consideration and is bound to perform.

This is why the statement describing a bilateral contract as requiring an equal promise to perform is the best fit: it captures the idea of two-sided promises forming the contract. The other statements don’t fit because contracts can be oral, not every bilateral contract requires a written form; consideration does exist in a bilateral contract since each party promises to do something; and modifying terms by mutual agreement can be enforceable, so changes don’t automatically render the contract unenforceable.