The estimated demand function: Q = -500 + 250 PI + 125 I - 1,000 I + 600 Asuggests that

Select one:

a. a 1 unit increase in PI will decrease the Q by 250 units

b. a 1% increase in PI will decrease the Q by 250%.

c. a 1% increase in PI will increase the Q by 250%.

d. a 1 unit increase in PI will increase the Q by 250 units.