In Welsh v.Lithia Vaudm,Inc. ,the case in the text,the court held that:

A) written agreements,such as an invoice,are presumed to be supported by consideration.
B) there was adequate consideration,making the arbitration clause enforceable.
C) no additional consideration existed where Lithia had a preexisting duty under the oral contract.
D) Lithia's modification was a pre-performance,bilateral demand.

Adequate Consideration

A fair and reasonable value exchanged in a contract, ensuring that all parties receive something of value.

Arbitration Clause

A provision in a contract that requires the parties to resolve disputes through arbitration rather than through litigation in court.

Preexisting Duty

An obligation that a party is already legally bound to, which cannot serve as consideration for a new contract.