Sarinda consumes crab cakes and tuna. Sarinda's utility increases with the consumption of crab cakes, but her utility neither increases nor decreases with the consumption of tuna. Assuming tuna is on the x-axis and crab cake is on the y-axis, what do Sarinda's indifference curves look like?a. vertical lines. b. downward-sloping lines. c. horizontal lines. d. upward-sloping lines from the origin