[单选题]
10.11: Consider the motion of an object given by the ve8h25 a brm4(.dpusbqrf(/i z13zufx funl83flocity vs. time graph shown. For which time(s) is8nf3f( 1ufzulfiz x 3/ 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