Several Charges in the Neighbourhood of Point P Produce an Electric

Multiple Choice

Several charges in the neighbourhood of point P produce an electric potential of 6.0 kV (relative to zero at infinity) and an electric field of N/C at point P.Determine the work required of an external agent to move a 3.0- $\mu$ C charge along the x axis from infinity to point P without any net change in the kinetic energy of the particle.

A) 21 mJ
B) 18 mJ
C) 24 mJ
D) 27 mJ
E) 12 mJ