[单选题]
A neutral atom has an electrxfk u1lns ,ldu- beo 15(zv2i:on configurat6jqqvp5l2 -yy )wvd n+ion 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
