[单选题]
As a freely falling obn. lrf:;ciyk*s,3cu aject speeds: ra)julgn773 kfhc;yoer3,b up, what is happening to its acceleration, how does it change if air friction CAN NOTr7c7rk f:3j 3loa;eub ,h y)ng be ignored?
A. keep the same
B. increase
C. decrease
D. hard to tell
