$\mathrm { A } + 5.0 - \mu \mathrm { C }$

Multiple Choice

$\mathrm { A } + 5.0 - \mu \mathrm { C }$ point charge is $12 \mathrm {~cm}$ from a $- 5.0 - \mu \mathrm { C }$ point charge. What is the magnitude of the electric field they produce at the point on the line connecting them where their electric potential (relative to infinity) is zero? $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 9.0 \times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 } \right)$

A) $12.5 \mathrm { MN } / \mathrm { C }$
B) $0 \mathrm {~N} / \mathrm { C }$
C) $0.75 \mathrm { MN } / \mathrm { C }$
D) $25 \mathrm { MN } / \mathrm { C }$
E) $1.5 \mathrm { MN } / \mathrm { C }$