An Object Is Moving Along the X Axis

An object is moving along the x axis. The graph shows its position from the starting point as a function of time. Various segments of the graph are identified by the letters A, B, C, and D.

-What is the acceleration of the object at t = 7.0 s?

A) zero m/s²
B) -2.0 m/s²
C) -3.0 m/s²
D) +9.8 m/s²
E) +4.0 m/s²