Which type of risk is insurable because it involves only the chance of loss or no loss, with no possibility of gain?

Why this is the answer

Insurance is designed around pure risk: situations where the only possibilities are suffering a loss or breaking even. A house fire is pure risk — you either lose the house or you don't; you can't profit from the house not burning. Speculative risk, such as investing in the stock market, adds a third outcome (gain) and is therefore uninsurable. Insurers pool pure risks across many policyholders so that predictable average losses can be funded from premiums, which is mathematically impossible if policyholders could profit from an outcome.