[单选题]
The energy acquired b ic1aj7rakfsraq/c k+s9 ,6v+y a particle ca(83 avo3csmrw0dvr c5rrying a charge equal to that on the electron as a result of moving through a potential difference of one volt is referred to wv0 (m5o vrr d8s3a3ccas
A. a joule.
B. an electron-volt.
C. a proton-volt.
D. a coulomb.
