Which statement BEST describes the doctrine of WAIVER in California insurance law?

Explanation

WAIVER is the voluntary and intentional relinquishment of a known right, which is what the response defining waiver that way and barring the insurer from later asserting a waived defense states. In California insurance law (see e.g., California Insurance Code §650 and case law), an insurer that knows of a policy defense (such as late payment, breach of a condition, or a misrepresentation) yet acts inconsistently with reliance on that defense — for example, accepting a late premium without reservation, or continuing to process a claim — may be held to have WAIVED the defense and cannot later assert it to deny coverage. ESTOPPEL is related but distinct: it focuses on the OTHER party's detrimental reliance on the first party's conduct, regardless of intent. The response demanding a written, notarized declaration fabricates a notarization requirement. The response treating waiver and estoppel as interchangeable overstates the equivalence — though both reach a similar result, the elements differ (intent vs. reliance). The response allowing only the insured to assert waiver is wrong; either party may waive a right.