The value of the 'spin only' magnetic moment for one of the following configurations is 2.84 BM. The correct one is :

Question

( A ) $d^4$ (in strong ligand field)
( B ) $d^3$ (in weak as well as in strong fields)
( C ) $d^5$ (in strong ligand field)
( D ) $d^4$ (in weak ligand field)