What is an agreement between the insured and the insurer that certain conditions will be met called?

The correct answer to this question is B. A warranty is a written guarantee between the insurance agency and the person who is insured that promises to repair or replaced the insured item(s) if conditions occur within a specified period of time. If either side breaches the warranty, it voids the contract and there is no longer an obligation.

An estoppel is basically a letter saying that the information one party stated is in fact true, and it is often used by landlords and tenants in real estate transactions. A client can have a certificate of insurance without having a warranty.