Which of the following would be covered under a building and personal property coverage form?

The selection of outdoor signs as the correct answer stems from the specifics of what a building and personal property coverage form typically covers. This form is designed to protect tangible property that is physically located at the premises, including buildings and their contents, as well as certain other property types associated with the insured location.

Outdoor signs are explicitly covered under this type of policy because they are considered part of the business property. They are an integral aspect of the business's ability to attract customers and signify the business's presence. Coverage usually extends to both the signs that are attached to the building and those that are standalone on the property.

In contrast, personal property while airborne would not typically be covered, as this type of coverage is meant for stationary property. Underground pipes generally fall outside the scope of coverage provided by standard building and personal property coverage forms, as these are usually considered part of the site infrastructure and not included within the policy. A building foundation is also typically not covered, as it is considered an integral part of the building structure and is often excluded from property coverage forms that emphasize movable and personal property.

Thus, outdoor signs are specifically included in the coverage, making this choice the correct one.