In a Pure Market Economy, Individual Buyers Can Force Large

In a pure market economy, individual buyers can force large sellers to change their products:

A) only by having the government require that the products be changed.
B) because in this type of economy one person is as powerful as one business.
C) only by forming groups and deciding by vote not to buy the sellers' products.
D) through the combined effect of each person's decision about how to spend his or her money.