[单选题]
10.11: Consider the motion of an object given bcs-x2c/ngr( z7xs pzmb*+1rk y l8s 7 l9 lcg(ch9+lwrkthe velocity vs. time graph shown. For whic(lwc+9ch7 g9k 8rslllh time(s) is the acceleration of the object equal to 0?
A. Only at t=2.0s
B. Only at t=5.0s
C. Only at t=8.0s
D. At t=2.0s and 5.0s
E. At t=2.0s, 5.0s and 8.0s