Answer:
b. substitutes in production
a. substitutes but not substitutes in production
Step-by-step explanation:
Complements are goods that are generally purchased or consumed together. An example would be ice cream and ice cream cones. Usually, when the price of a good rises, its demand decreases, and so does the demand for its complement. On the other hand, a substitute is a good that is purchased or consumed in place of another one. In this example, leather purses and leather shoes are substitutes, but only in production. On the other hand, SUVs and pickup trucks are substitutes, but not substitutes in production.