Morris Has the Utility Function U(b, W)= 3b + 3w

Morris has the utility function U(b, w) = 3b + 3w and Philip has the utility function U(b, w) = bw, where b is the number of books consumed per month and w is bottles of wine consumed per month.If we draw an Edgeworth box with books on the horizontal axis and wine on the vertical axis and if we measure Morris's consumptions from the lower left corner of the box, then the contract curve contains

A) a straight line running from the upper right corner of the box to the lower left.
B) a curve that gets steeper as you move from left to right.
C) a straight line with slope 1/1 passing through the lower left corner of the box.
D) a straight line with slope 1/1 passing through the upper right corner of the box.
E) a curve that gets flatter as you move from left to right.