Which of the following is an example of derived demand?

a. A decrease in the prices of oranges has led to more orders of orange juice.

b. An increase in coffee drinking is prompting coffee shops to order more coffee grinders.

c. Sales for bathing suits jump in the summer, especially in hotter regions.

d. An increase in windshields has led to an increase in windshield wipers.

e. An increase in airfare prices has not had much of an effect on demand for business travelers.