Two 30 μC Charges Lie on the X-Axis,one at the Origin

Multiple Choice

Two 3.0 μC 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? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

A) 11,000 V
B) 9000 V
C) 14,000 V
D) 3400 V