Which structure is integral to how insurance is underwritten at Lloyd's?

The correct answer is that syndicates are integral to how insurance is underwritten at Lloyd's. In the Lloyd's insurance market, syndicates are groups of investors or underwriters who come together to pool their resources to underwrite insurance policies. Each syndicate specializes in certain types of risks and operates independently, determining its own underwriting criteria and pricing.

This structured approach allows for a diverse range of risks to be managed across multiple participants, creating a competitive environment that can lead to innovations in policy structures and pricing. Syndicates collectively contribute to the overall capacity of Lloyd's to absorb large or complex risks, and this collaboration among multiple syndicates facilitates a more stable insurance market.

The other options presented, such as pools, alliances, and unions, do not specifically describe the unique underwriting framework employed at Lloyd's. While pools may refer to groups that combine resources for collective risk management, they lack the distinct operational structure and specialization inherent to syndicates within the Lloyd's framework. Hence, syndicates are the defining element in Lloyd's underwriting process.