Dealing in the commodity of oil, an initial maintenance requirement of $6,000 exists on a contract of 1,000 barrels of oil at $75 per barrel with a maintenance margin of $4,500. If the price of oil increases, how does the use of margin affect return? a. Return is amplified in a negative direction. b. Return is dampened in a positive direction. c. Return is dampened in a negative direction. d. Return is amplified in a positive direction