Co-insurance in health insurance means:

Comprehensive insurance refers to a type of policy that covers a wide range of risks and services, not specifically related to co-insurance. It typically encompasses various healthcare services but does not define the cost-sharing mechanism that co-insurance represents.

A stop-loss provision is a feature in health insurance that limits the amount the insured will pay out of pocket. Once this limit is reached, the insurer covers 100% of additional costs. While it relates to overall costs, it does not explain the co-insurance concept, which focuses on shared expenses before any stop-loss threshold is met.

Percentage sharing is a vague term that does not specifically define co-insurance. While it implies that costs are shared as a percentage, it lacks the clarity of the term "shared losses in agreed proportion," which accurately outlines the contractual nature of co-insurance agreements.