Four identical charges \[+\,50\,\mu C\] each are placed, one at each corner of a square of side \[2\,m\]. How much external energy is required to bring another charge of \[+\,50\,\mu C\] from infinity to the centre of the square \[\left( \text{Given}\frac{\text{1}}{\text{4}\pi {{\varepsilon }_{\text{0}}}}=9\times {{10}^{9}}\frac{N{{m}^{2}}}{{{C}^{2}}} \right)\]

• A.                    \[64\,J\]
• B.            \[41\,J\]
• C.                    \[16\,J\]
• D.                                      \[10\,J\]