Suppose One Observes That When the Price of Peanut Butter

Multiple Choice

Suppose one observes that when the price of peanut butter increases, the demand for jelly increases. One must conclude that:

A) peanut butter and jelly are complements.
B) peanut butter and jelly are substitutes.
C) peanut butter and jelly are normal goods.
D) peanut butter and jelly are inferior goods.