A cheetah can go from a state of resting to running at 20 m/s in just two seconds. What is the cheetah's average acceleration?
A40 m/s^2
B40 m/s
C10 m/s
D10 m/s^2
A40 m/s^2
B40 m/s
C10 m/s
D10 m/s^2