What Is the Magnitude of a the Vertical Electric Field $2.1 \mathrm {~g}$

What is the magnitude of a the vertical electric field that will balance the weight of a plastic sphere of mass $2.1 \mathrm {~g}$ that has been charged to $- 3.0 \mathrm { nC }$ ? $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 9.0 \times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 } \right)$

A) $1.5 \times 10 ^ { 6 } \mathrm {~N} / \mathrm { C }$
B) $6.9 \times 10 ^ { 6 } \mathrm {~N} / \mathrm { C }$
C) $7.8 \times 10 ^ { 5 } \mathrm {~N} / \mathrm { C }$
D) $2.1 \times 10 ^ { 6 } \mathrm {~N} / \mathrm { C }$