$[\overset{-1}{\mathop{Mn}}\,{{(CO)}_{4}}(N{{O}^{+}})]:$ No unpaired $e^-$ either on ligands or on $\overset{-1}{\mathop{Mn}}$ hence it is diamagnetic
$(P)\, Fe(CO)_5\,\,\, (Q)\,CO\,\,\, (R)\, H_3B \leftarrow CO\,\,\,(S)\, [Mn(CO)_5]^-$
($en=$ ઇથિલીન ડાય એમાઈન)