Waldo's utility function is U(x, y) = xy. Waldo consumes 5 units of x and 25 units of y.
Which statement is true?

a. Waldo would be willing to make small exchanges of x for y in which he would give up 5
units of x for every unit of y he got.

b. Waldo would be willing to trade away all of his x for y as long as he got more than 5
units of y for every unit of x he gave up.

c. Waldo likes x and y equally well so he is always willing to exchange 1 unit of either good
for more than 1 unit of the other.

d. Waldo will always be willing to make trades at any price if he does not have equal
amounts of the two goods.

e. None of the above.