[单选题]
The net work done in moving an elect.o9 u. mck6qsm:- bvpyron from pe 2wen 8 vd 5gse;5wv34zn2lhaoint A, where the potential is -50 V, to point B, ;v4l2dnevwh82eg n3ae5 s 5zwwhere 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
