C

To find the torque acting on a dipole in an electric field, we use the formula:
Torque (τ) = p × E
where 'p' is the dipole moment and 'E' is the electric field.
If the dipole is aligned or anti-aligned with the field, the angle between p and E would be either 0° or 180°. In this case, if the dipole is not aligned or misaligned in the field, the torque can be computed.
However, in the case where the dipole moment is zero or the electric field is constant throughout, the net torque would be zero.
Therefore, the torque on the dipole in the electric field is Zero.