Match the Effects on the Rate of Gas Transfer, Labelled

Match the effects on the rate of gas transfer, labelled a. through c., with the changes listed. (Options may be used more than once or not at all.)
-the effect of a fall in atmospheric PO₂ on O₂ exchange within the lungs

A) This change would increase the rate of gas transfer.
B) This change would decrease the rate of gas transfer.
C) This change would have no effect on the rate of gas transfer.