Suppose one observes that when the price of peanut butter increases, the demand for jelly increases. One must conclude that:
选项:
A:peanut butter and jelly are complements.;
B:peanut butter and jelly are inferior goods.;
C:peanut butter and jelly are normal goods.;
D:peanut butter and jelly are substitutes.
发布时间:2024-06-05 19:04:16