Fred Loves Tomatoes

Multiple Choice

Fred loves tomatoes.He makes soups,sauces,and stews with them; stuffs them; roasts them; and grills them.Fred has discovered a farmer's market where the price of a bushel of tomatoes depends on how many bushels are purchased.The first bushel is $15; the second,$12; the third,$10; and four or more,$9 each.Fred has $82 to spend on tomatoes and on "all other things" during the coming week.All other things sell for $1 per unit.Assume that all other things are measured on the vertical axis.What is Fred's marginal rate of substitution if he chooses to buy 5 bushels of tomatoes?

A) -9.
B) 0.10.
C) 12.
D) 1/15.
E) 1/9.