The graph in the figure shows the variation of the electric potential v(x) (in arbitrary units) as a function of the position x (also in arbitrary units). which of the choices below correctly describes the orientation of the x-component of the electric field along the x-axis?
a. ex is positive from x = -2 to x = 0, and negative from x = 0 to x = 2.
b. ex is negative from x = -2 to x = 0, and positive from x = 0 to x = 2.
c. ex is negative from x = -2 to x = 2.
d. ex is positive from x = -2 to x = 2.