Explanation:

- Novation: This involves replacing an old contract with a new one, which may involve changing parties, terms, or obligations.

- Remission: This is forgiving a debt or obligation, where a party agrees to accept less than what was initially due or owed.

- Rescission: This means canceling a contract as if it never existed, undoing both existing and future obligations.

- Waiver: This is the voluntary relinquishment of a right or claim under the contract.

- Correct Answer: Rescission: When certain terms or all terms of a contract are canceled, it is called discharge by rescission.