Gas that leaked inside a dwelling insured on an unendorsed basic form ignites and blows out a kitchen wall. The loss is:

解析

Fire, lightning, and internal explosion are the three perils the unendorsed basic form insures, so an explosion occurring inside the described dwelling is covered as the form stands. The endorsement answer confuses this with the broader explosion peril that reaches blasts originating outside the building. The form pays the resulting building damage, not merely appliances.