Three charges Q, +q and -q are placed at the vertices of a right angled isosceles triangle as shown below. The net electrostatic energy of the configuration is zero, if the value of Q is

• A. -2q
• B. \( - \frac{q}{{1 + \sqrt 2 }}\)
• C. +q
• D. \( - \frac{{\sqrt 2 q}}{{\sqrt 2 + 1}}\)