Consider this scenario.

-In recent years many Americans have started to pay more attention to the amount of sugar and calories in their diet.
-Some soft drink companies are concerned about consumers' desire to be healthier.
-They believe that this could result in a drop in demand for their products.

Which factor affecting demand does this scenario illustrate?
A.a change in the number of people in the population
B.a change in the price of a substitute good from a rival soft drink company
C.a change in consumer tastes and preferences
D.a change in the price of a complementary good from a potato chip company