In a Region Where the Electric Field Is Uniform and Points

In a region where the electric field is uniform and points in the $+ x$ direction, the electric potential is $- 2000 \mathrm {~V}$ at $x = 8 \mathrm {~m}$ and is $+ 400 \mathrm {~V}$ at $x = 2 \mathrm {~m}$ . What is the magnitude of the electric field?

A) $200 \mathrm {~V} / \mathrm { m }$
B) $600 \mathrm {~V} / \mathrm { m }$
C) $300 \mathrm {~V} / \mathrm { m }$
D) $400 \mathrm {~V} / \mathrm { m }$
E) $500 \mathrm {~V} / \mathrm { m }$