7. Assume that preferences are complete, transitive, monotonic and convex and consider the truthfulness of the following statements. I. If Doug's income consumption curve for good at and good y is upward sloping, the demand curve for good y must be downward sloping. II. If the Engel curve for good x is vertical, then the law of demand must hold for good x. a. Only statement I is tme. b. Only statement 11 is true. 0. Both statements I and II are true. d. Neither statement is true