A Small $4.0 - \mu C$ Charge and a Small $1.5 - \mu C$

Multiple Choice

A small $4.0 - \mu C$ charge and a small $1.5 - \mu C$ charge are initially very far apart. How much work does it take to bring them to a final configuration in which the $4.0 - \mu \mathrm { C }$ charge is at the point $x = 1.0$ $\mathrm { mm } , y = 1.0 \mathrm {~mm}$ , and the $1.5 - \mu \mathrm { C }$ charge is at the point $x = 1.0 \mathrm {~mm} , y = 3.0 \mathrm {~mm}$ ? $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 8.99 \right.$ $\times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 }$ )

A) $13.5 \mathrm {~kJ}$
B) $27 \mathrm {~J}$
C) $13.5 \mathrm {~J}$
D) $54 \mathrm {~J}$