GKFix MCQ Question

What is the potential at point D due to the charge at C (+q) at distance d?

• A. -\frac{q}{4\pi\epsilon_0 d}
• B. +\frac{q}{4\pi\epsilon_0 d}
• C. Zero
• D. \frac{q}{4\pi\epsilon_0 d\sqrt{2}}