If we graph Mary Granola's indifference curves with avocados on the horizontal axis and grapefruits on the vertical axis, then whenever she has more grapefruits than avocados, the slope of her indifference curve is -2. Whenever she has more avocados than grapefruits, the slope is -1/2. Mary would be indifferent between a bundle with 12 avocados and 17 grapefruits and another bundle that has 37 avocados and

a.2 grapefruits.

b.22 grapefruits.

c.17 grapefruits.

d.12 grapefruits.