If the principal quantum number n56, the correct sequence of filling of electrons will be :

Question

( A ) $ns \to (n-1) f \to (n-2) d \to np$
( B ) $ns \to np \to (n-1) d \to (n-2) f$
( C ) $ns \to (n-2) f \to (n-1) d \to np$
( D ) $ns \to (n-2) f \to np \to (n-1) d$