The Figure Shows Two Tiny $5.0 - \mathrm { g }$

The figure shows two tiny $5.0 - \mathrm { g }$ spheres suspended from very light $1.0$ -m-long threads. The spheres repel each other after each one is given the same positive charge and hang at rest when $\theta$ $= 4.1 ^ { \circ }$ . What is the charge on each sphere $? \left( k = 1 / 4 \pi \varepsilon _ { 0 } = 9.0 \times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 } \right)$

A) $360 \mathrm { nC }$
B) $89 \mathrm { nC }$
C) $22 \mathrm { nC }$
D) $180 \mathrm { nC }$
E) $45 \mathrm { nC }$