Five identical conducting plates, each of face area \(\mathrm{A}\) are placed parallel to each other with a separation of ' \(d\) ' between two adjacent plates as shown in the figure. The plates \(\mathrm{M}\) and \(\mathrm{N}\) are given charges \(Q_1\) and \(Q_2\) respectively and the remaining plates are neutral. If the outermost plates are grounded, the potential difference between the plates \(\mathrm{M}\) and \(\mathrm{N}\) is ____

1. A \(\frac{2 \mathrm{~d}\left(\mathrm{Q}_1-\mathrm{Q}_2\right)}{\epsilon_0 \mathrm{~A}}\)
2. B \(\frac{\mathrm{d}\left(\mathrm{Q}_1-\mathrm{Q}_2\right)}{2 \epsilon_0 \mathrm{~A}}\)
3. C \(\frac{4 \mathrm{~d}\left(\mathrm{Q}_1-\mathrm{Q}_2\right)}{\epsilon_0 \mathrm{~A}}\)
4. D \(\frac{\mathrm{d}\left(\mathrm{Q}_1-\mathrm{Q}_2\right)}{4 \epsilon_0 \mathrm{~A}}\)