Answer
C. $a_{c}>a_{b}>a_{b}$
Work Step by Step
To go from velocity to acceleration, you want to look at their slopes. The slope at point c is positive, the slope at point b is zero, and the slope at point a is negative. Thus, going from most positive to least positive would be in the only positive point given to us, the point where the slope is zero, and the point where the slope is negative.
