----How are you going, buddy?

----________. A little busy, though.

A．Can’t be worse

B．By train

C．Not too bad

D．on my own

将物体竖直上抛，假设运动过程中空气阻力不变，其速度一时间图象如图所示，则物体所受的重力和空气阻力之比为

A.1:10

B. 10:1

C. 9:1

D. 8:1