The electric potential energy of an electric dipole is when the dipole is aligned with an electric field. The electric potential energy of an electric dipole is when the dipole is aligned with an electric field. most positive most negative zero infinite undefined

Most negative

Explanation:

The electric potential energy of a dipole U = -pEcosθ where p = dipole moment, E = electric field and θ = angle between p and E.

When the electric dipole is aligned with the electric field, the angle between p and E is 0°. That is θ = 0°.

So, U = -pEcosθ

U = -pEcos0°

U = -pE

which is the most negative value it can have.

So, the electric potential energy of an electric dipole is most negative when the dipole is aligned with an electric field.

So, most negative is the answer.