The d-electron configurations of $Cr^{2+}, Mn^{2+}, Fe^{2+}$ and $Co^{2+}$ are $d^4, d^5, d^6$ and $d^7$ respectively. Which one of the following will exhibit minimum paramagnetic behaviour ? <br> (At. Nos. Cr= 24, Mn= 25, Fe= 26, Co = 27)

Question

( A ) $[Co(H_2O)_6]^{2+}$
( B ) $[Mn(H_2O)_6]^{2+}$
( C ) $[Fe(H_2O)_6]^{2+}$
( D ) $ [Cr(H_2O)_6]^{2+}$