During repairs, which of these costs could influence the determination of substantial damage?

The correct choice relates specifically to costs incurred for clearing debris. In the context of assessing substantial damage under the National Flood Insurance Program (NFIP), the costs of repair and replacement are critical factors. Substantial damage refers to damage that meets or exceeds a specific percentage of the structure's value, and this assessment includes all costs associated with bringing the building back to its pre-damage condition.

Clearing debris can be a significant cost that follows a flood event and must be factored into the total cost of repairs. This includes expenses for removing materials, rubbish, and other items that may obstruct the repair process and contribute to the overall expense needed to restore the property to its original state, thus affecting substantial damage determinations.

Other options such as fees for permits, upgrades to non-structural elements, and landscaping improvements may not be directly included in the calculation of substantial damage. Permit fees are administrative costs, upgrades don't typically relate to the essence of the substantial damage determination, and landscaping done prior to a flood event is generally not considered part of the structural repair costs necessary for assessing damage. Hence, they would not influence the determination of substantial damage in this case.