# If the electric potential at point A is $20\;V$ and at $B$ is $– 40\; V$, then

(A) The work done by an external force in moving an electron slowly from B to A is $-9.6 \times 10^{18} J$
(B) The work done by an electrostatic force in moving an electron slowly from B to A is $-9.6 \times 10^{-18} \;J$