The Force of Attraction That A $- 40.0 \mu \mathrm { C }$

The force of attraction that a $- 40.0 \mu \mathrm { C }$ point charge exerts on $\mathrm { a } + 108 \mu \mathrm { C }$ point charge has magnitude $4.00 \mathrm {~N}$ . How far apart are these two charges? $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 8.99 \times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 } \right)$

A) $2.10 \mathrm {~m}$
B) $3.12 \mathrm {~m}$
C) $2.49 \mathrm {~m}$
D) $3.67 \mathrm {~m}$
E) $1.13 \mathrm {~m}$