Two $3.0 \mu \mathrm { C }$ Charges Lie on The $x$

Two $3.0 \mu \mathrm { C }$ charges lie on the $x$ -axis, one at the origin and the other at $2.0 \mathrm {~m}$ . What is the potential (relative to infinity) due to these charges at a point at $6.0 \mathrm {~m}$ on the $x$ -axis? $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 9.0 \times 10 ^ { 9 } \right.$ $\mathrm { N } \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 }$ )

A) $3400 \mathrm {~V}$
B) $11,000 \mathrm {~V}$
C) $14,000 \mathrm {~V}$
D) $9000 \mathrm {~V}$