Which of the Following Statements Is True

Which of the following statements is true?

A) Contractual terms are only binding if both parties sign a document which contains those terms.
B) Contractual terms are only binding if they are embodied in a document, whether written or typed, and both parties receive a copy.
C) Express terms may only be agreed to in writing. Implied terms may only be agreed to orally.
D) Parties may be bound to terms they have agreed to orally without ever putting them in writing.