[单选题]
Which of the following is equivalent tyk/o(c.,1epsl 3ph4fyaxrt 9ti( jxh/p 17md o the unit o2gi ryr23sxwb,); q6goy3 k6 qb:,+ cdietqtxf electric potential difference) bq2t2gr ,wys3+gixr6dx,q;: t eiqoc36 bk y?
A. $NmC ^{−1}$
B. $Nm^{−1}C^{−1}$
C. $JC$
D. $Jm^{−1}C^{−1}$
