At Auction Experts Expect a Jacques Plante Hockey Card to Get

At auction experts expect a Jacques Plante hockey card to get a higher price than Sidney Crosby's rookie card.Which of the following events would cause the price difference in these cards to get smaller?

A) The demand for Crosby cards decreases.
B) The supply of Crosby rookie cards increases.
C) The demand for Crosby rookie cards increases and the supply of Plante cards increases.
D) The demand for Crosby rookie cards decreases and the demand for Plante cards increases.