The correct answer is D — Flood. Standard homeowners insurance does not treat flood as one of its basic insured perils. Flood is generally excluded from ordinary homeowners property coverage and normally requires separate flood insurance, such as coverage obtained through the National Flood Insurance Program or an eligible private flood insurer.

By contrast, riot or civil commotion, smoke, and volcanic eruption are among the standard named causes of loss appearing in homeowners forms. The Insurance Information Institute's comparison of homeowners perils identifies riot/civil commotion, smoke, and volcanic eruption as covered causes while explaining that flood requires separate protection.

The exclusion of flood is particularly important for adjusters because “water damage” is not a single coverage category. The adjuster must determine the actual mechanism and source of water—such as plumbing leakage, rain entering through covered storm damage, surface water, tidal overflow, sewer backup, or flood—and then apply the specific policy language.

The official Series 17-70 outline requires knowledge of the Homeowners 2011 Policy, including perils insured against, exclusions, and conditions. It separately identifies the National Flood Insurance Program elsewhere in the broader property curriculum.

Therefore, the peril that is not a basic homeowners peril is D — Flood.