If the foundations of all the columns of a structure are designed on the total live and dead load basis, then

Answer: Option D

Concept: When all footings are proportioned on the basis of total load (dead + full live load), the design aims to keep the same allowable soil pressure under every footing at the notional maximum loading condition.

Reality of loading: In service, the live load is not fully present everywhere at the same time, and interior columns generally have larger tributary areas than exterior columns. Hence, interiors attract higher actual loads more often.

Resulting behavior: Because interior footings experience higher sustained/actual pressure relative to exterior footings, they undergo greater compression of the supporting soil.

Conclusion: Differential settlement occurs with the interior columns settling more than the exterior columns.