On an ISO DP-1 Basic Form Dwelling policy without endorsements, how are covered losses to the dwelling settled?

Why this is the answer

The ISO DP-1 Basic Form is the most stripped-down dwelling form and settles losses on an actual cash value (ACV) basis, which is replacement cost minus depreciation. Unlike the DP-2 and DP-3, which automatically include replacement-cost settlement on the dwelling at 80% coinsurance, the DP-1 reverts to ACV unless the insured elects a Replacement Cost endorsement. This default reflects DP-1's positioning as a low-cost form for older or lower-valued dwellings (ISO DP 00 01 Section I Loss Settlement).