Correct answer = A. Niacin.
At gram doses, niacin strongly inhibits lipolysis in adipose tissue—the primary producer of circulating free fatty acids.
The liver normally utilizes these circulating fatty acids as a major precursor for triglyceride synthesis. Thus, niacin causes a decrease in liver triglyceride synthesis, which is required for VLDL production. The other choices do not inhibit lipolysis in adipose tissue.