What is waiver, and when can it be revoked or relied upon?

• A. Waiver is a temporary postponement of a right.
• B. Waiver is a voluntary relinquishment of a known right; it is always irrevocable.
• C. Waiver is a voluntary relinquishment of a known right; revocation is never allowed.
• D. Waiver is a voluntary relinquishment of a known right; it can be revoked or relied upon based on equitable grounds or reliance.

Answer: (D)