A

To determine the angle at which the torque on an electric dipole in a uniform electric field is maximum, recall the expression for torque (\tau) on a dipole given by the formula:\
\tau = \vec{p} \times \vec{E} = pE \sin(\theta)\
where \(\tau\) is the torque, \(\vec{p}\) is the dipole moment, \(\vec{E}\) is the electric field, and \(\theta\) is the angle between the dipole moment and the electric field.
The torque is maximum when \(\sin(\theta) = 1\), which occurs at \(\theta = 90^{\circ}\). Therefore, the torque on the dipole will be maximum at an angle of 90 degrees between the dipole moment and the electric field.