[单选题]
A neutral atom has an electrewhvn rve7bg.f2-; 4 4 maiky.on conrpf 2q/b;h. mpfiguration of $1s^22s^22p^6$. If a neutral atom holds one additional electron, what is the ground state configuration?
A. $1s^22s^22p^63s^1$
B. $1s^22s^22p^7$
C. $1s^22s^32p^6$
D. none of the given answers
