The correct option is D deficit
Surplus means more than what is needed or used; excess. The opposite of surplus is deficit, or an amount by which a resource, especially money, falls short of what is required. Hence, Option D is correct. Among the rest of the options, reduction means the action or fact of making something smaller or less in amount, degree, or size, shortness means the quality of being relatively small in height or length, loss means the fact or process of losing something or someone.These options do not express this antonym, hence incorrect