Which of the following is a requirement for an insurer to conduct business in a state?

To conduct business in a state, an insurer must obtain a certificate of authority. This document is crucial as it grants the insurer legal permission to operate within that specific state. The certificate of authority ensures that the insurer meets all regulatory requirements set forth by the state's insurance department, including financial stability, compliance with state laws, and adherence to consumer protection standards. Without this certificate, an insurer cannot legally sell insurance products or offer services to residents of the state. This requirement helps maintain the integrity and governance of the insurance industry, ensuring that only qualified and regulated companies can provide insurance coverage to consumers.

While licensing agreements, state registrations, and market approval may hold significance in various contexts, they do not specifically serve as the primary legal authorization that allows an insurer to conduct business within a state. The certificate of authority is the direct requirement for insurers to operate legally and effectively in that jurisdiction.