The outer electron configuration of Gd (Atomic No:64) is :

Question

( A ) $4f^7 5d^1 6s^2$
( B ) $4f^4 5d^4 6s^2$
( C ) $4f^8 5d^0 6s^2$
( D ) $4f^3 4d^5 6s^2$