A point charge q moves from point P to pont S along the path PQRS (fig.) in a uniform electric field E pointing parallel to the poistive direction of the X-axis. The coordinates of the points P, Q, R and S are(a, b, O), (2a, O, O)(a, -b,`ulO`) and `(O, O, O) respectively. The work done by the field in the above process is given by the expresison............

Options

A. q E a
B. `-q E a`
C. `q E a sqrt(2)`
D. `qEsqrt([(2a)^(2) + b^(2)])`

Answer

B