Two identical thin rings each of radius R meters are coaxially placed at a distance R meters apart. If \[{{Q}_{1}}\]coulomb and \[{{Q}_{2}}\]coulomb are respectively the charges uniformly spread on the two rings, the work done in moving a charge q from the center of one ring to that of other is

• A. zero                  
• B.        \[\frac{q\left( {{Q}_{1}}-{{Q}_{2}} \right)\left( \sqrt{2}-1 \right)}{\sqrt{2}.4\pi {{\varepsilon }_{0}}R}\]
• C. \[\frac{q\sqrt{2}\left( {{Q}_{1}}+{{Q}_{2}} \right)}{4\pi {{\varepsilon }_{0}}R}\]                                   
• D. \[\frac{q\left( {{Q}_{1}}+{{Q}_{2}} \right)\left( \sqrt{2}+1 \right)}{\sqrt{2}.4\pi {{\varepsilon }_{0}}R}\]