1. Electric field due to an infinite plane sheet
   For an infinite plane sheet with uniform positive surface charge density $\sigma_0$, the electric field is $E = \frac{\sigma_0}{2\varepsilon_0}$ and it is uniform (independent of distance from the sheet) and directed away from the sheet.

So at the position of the dipole, the field is constant in magnitude and direction.

2. Force on an electric dipole in a uniform electric field
   A dipole in a uniform electric field experiences no net force because the forces on $+q$ and $-q$ are equal and opposite.

Hence, options involving a net force toward or away from the sheet are incorrect.

So:

• A is wrong
• D is wrong

3. Torque on a dipole in an electric field
   Torque on a dipole is $\tau = pE\sin\theta$ where $\theta$ is the angle between dipole moment $\vec p$ and electric field $\vec E$.

Torque is zero when: $\theta = 0 \quad \text{or} \quad \pi$ That is, when the dipole is parallel or anti-parallel to the field.

Since the options mention torque being zero together with potential energy conditions, we examine the stable case.

4. Potential energy of a dipole in an electric field
   Potential energy is $U = -\vec p\cdot \vec E = -pE\cos\theta$

• For $\theta=0$: $U_{\min} = -pE$ This is the minimum potential energy.
• For $\theta=\pi$: $U_{\max} = +pE$ This is the maximum potential energy.

Thus, when the dipole is in stable equilibrium, torque is zero and potential energy is minimum.

5. Check options

• A: Torque zero but net force away from sheet $\to$ wrong, because net force is zero.
• B: Potential energy minimum and torque zero $\to$ correct.
• C: Potential energy and torque both maximum $\to$ wrong, because when potential energy is maximum ($\theta=\pi$), torque is still zero, not maximum.
• D: Torque zero and net force toward sheet $\to$ wrong, because net force is zero.

6. Final answer
   The correct option is: $\boxed{\text{B}}$

This matches the stored correct answer.