$\mathrm { A } + 4.0 - \mu \mathrm { C }$

Multiple Choice

$\mathrm { A } + 4.0 - \mu \mathrm { C }$ and a $- 4.0 - \mu \mathrm { C }$ point charge are placed as shown in the figure. What is the potential difference between points $A$ and $B$ ? $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 9.0 \times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 } \right)$

A) $96 \mathrm { kV }$
B) $0 \mathrm {~V}$
C) $48 \mathrm { kV }$
D) $48 \mathrm {~V}$
E) $96 \mathrm {~V}$