[单选题]
The net work done in movi*xht( lg4ktlq42h4a z ng an electron from point A, where the potential issu34.0 xof i 1rd.baal -50 V, to point B, where the potential is +roafds.i0lax b1 4. 3u50 V, is
A. $+1.6 \times 10^{-17} \; J$.
B. $-1.6 \times 10^{-17} \; J$.
C. zero.
D. none of the given answers
