【单选题】Joe likes peanut butter and jelly sandwiches for lunch. We can conclude that for Joe the cross elasticity of demand for peanut butter with respect to jelly is (乔喜欢花生酱和果冻三明治吃午饭。我们可以得出结论,对于乔来说,花生酱对果冻的需...
A.
positive because jelly and peanut butter are substitutes.积极因为果冻和花生酱是替代品。
B.
positive because jelly and peanut butter are complements.积极因为果冻和花生酱是补充。
C.
negative because jelly and peanut butter are substitutes.消极因为果冻和花生酱是替代品。
D.
negative because jelly and peanut butter are complements.消极因为果冻和花生酱是补充。