[单选题]
The energy acquired by a particlur5k:/bt gg-ldk5obd 3 u ;5oye carrying a charge equ(2ww8gg iwuyw90 2 qwy:l(/ay)g ttpual to that on the electron as a result of moving through a potential difference of one volt i)ug9qi2 tw80 gyw/:wypu( (l w2tgayws referred to as
A. a joule.
B. an electron-volt.
C. a proton-volt.
D. a coulomb.