[单选题]
The net work done in moving 6q4ps n9wt+dhan electron from point A, where the 6 bb lrvkef x60g3aq.4eohp:fz6, vk-potential is -50 V, to point g 6o:b,.3frfp6qkkae6ve h0 lzvbx -4B, where the potential is +50 V, is
A. $+1.6 \times 10^{-17} \; J$.
B. $-1.6 \times 10^{-17} \; J$.
C. zero.
D. none of the given answers
