FIGURE 3-1 Refer to Figure 3-1

FIGURE 3-1 Refer to Figure 3-1.The movement along the demand curve,D,from point v to point x,could be caused by

A) a change in preferences away from ordinary light bulbs to energy-efficient light bulbs.
B) a change in the price of energy-efficient light bulbs.
C) an increase in household income,which allows consumers to purchase more light bulbs.
D) a change in the price of ordinary light bulbs.
E) an expectation that new,government regulations will require the use of energy-efficient light bulbs only.