After an unexplained loss to a dwelling written on an open-perils form, the burden of proof:

解析

Open-perils wording reverses the usual burden. The insured shows a direct physical loss, and the insurer must point to an exclusion to deny it. The answer making the insured name the peril states the rule for a named-perils form such as the basic or broad dwelling policy, where the loss must be matched to a listed cause.