The graph between the displacement x and time t for a particle moving in a straight line is shown in figure. During the interval OA, AB, BC and CD, the acceleration of the particle is
a) (+, 0, +, +) b) (-, 0, +, 0) c) (+, 0, -, +) d) (-, 0, -, 0)
-
UP 0 DOWN 0 0 0
