Potential Due to Point-Charges: Two Point Charges of +2

Potential due to point-charges: Two point charges of +2.0 μC and -6.0 μC are located on the x-axis at x = -1.0 cm and x = +2.0 cm respectively. Where should a third charge of +3.0-μC be placed on the +x-axis so that the potential at the origin is equal to zero? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

A) x = 4.0 cm
B) x = 1.0 cm
C) x = 2.0 cm
D) x = 3.0 cm
E) x = 5.0 cm