Which one is the correct expression of electric potential on the axial point of a dipole whose dipole moment is p and length is 2l, at a distance of r?

MCQs on electrostatic potential, potential due to point charge and electric dipole, equipotential surfaces, potential energy in external field, conductors electrostatics, dielectrics, polarisation, capacitors, capacitance, parallel plate capacitor, dielectric capacitance effects, capacitors combination and van de graff generator.