[单选题]
A neutral atom has an electroam -l5s4kqgki1*fv l4n configuration a ggt5nc5kv.e 20p 2ptof $1s^22s^22p^6$. 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
