The demand for video recorders has been estimated to be Qv = 134 - 1.07Pf + 46Pm - 2.1Pv - 5I, where Qv is the quantity of video recorders, Pf denotes the price of video recorder film, Pm is the price of attending a movie, Pv is the price of video recorders, and I is income. Based on the estimated demand equation we can conclude:
a. the demand for video recorders is inelastic.
b. the demand for video recorders is neither inferior nor inelastic, and video recorder film is not a substitute for video recorders.
c. video recorders are inferior goods.
d. video recorder film is a substitute for video recorders.