[Dog Training] Nia and Bruno Enter into a Written Contract

Multiple Choice

[Dog Training] Nia and Bruno enter into a written contract for Bruno to train Nia's dog. Under the contract, Nia is required to pay Bruno $20 for each training session.
-Which of the following is true about void and voidable contracts?

A) Either party can terminate the contract at any time as long as additional consideration is paid.
B) Both contracts are illegal and the consideration for the contract must be returned to the other party.
C) Both parties must agree to terminate a void or a voidable contract because otherwise there would be no privity of contract and a court would not uphold it anyway.
D) A void contract is not a contract at all; a voidable contract can be terminated by one party.
E) Both contracts must be in writing.