If the price consumption curve of good X, which is on the horizontal axis, slopes down- ward, we can be sure that as the price of good X falls: a) consumers spend less money on X even though they buy more of it. b) consumers spend the same proportion of their budget on X, even though they buy more of it. c) consumers spend more money on X. d) None of the above is necessarily true, because the information provided does not allow us to determine what happens to the amount spent on X as the price of X falls.