The species having 4 or more unpaired electrons are:

The species having 4 or more unpaired electrons are ${\mathrm{Fe}}^{2+}$,${\mathrm{Co}}^{3+}$and ${\mathrm{Mn}}^{2+}$.

The number of unpaired electrons for Fe2+,Co3+,Mn2+ and Ni2+ are 4,4,5 and 2 respectively.

There are four unpaired electrons are present in the Fe2+ ion as, The electronic configuration of Fe+2 is [Ar]3d6,4s∘ 

The two electrons in the 4s are lost as nickel ionizes to the +2 state, leaving Ni2+ with two unpaired electrons.

Hence, the species having 4 or more unpaired electrons are ${\mathrm{Fe}}^{2+}$,${\mathrm{Co}}^{3+}$,${\mathrm{Mn}}^{2+}$.

Therefor, option A, B and C are correct.