At Their Current Distributions,Andrew's Marginal Rate of Substitution of Hamburgers

Multiple Choice

At their current distributions,Andrew's marginal rate of substitution of hamburgers for fish sticks is 6 while Betty's is 2.Both Andrew and Betty could be made better off if:

A) they do not trade and keep their present allotment of hamburger and fish sticks.
B) Andrew trades between two and six of his allotment of hamburgers with Betty for a fish stick.
C) Andrew trades between two and six of his allotment of fish sticks with Betty for a hamburger.
D) Andrew gives all of his hamburgers to Betty for all of her fish sticks.