Find the difference in the EAN value. if the NO ligand is considered as neutral and if NO ligand is considered as positive ligand in $\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_5{\mathrm{NO}}_3{\mathrm{SO}}_4\right.$ complex

The total number of electrons encircling a metal atom's nucleus in a metal complex is represented by the EAN number. 

In complex $\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_5{\mathrm{NO}}_3{\mathrm{SO}}_4\right.$

If NO is neutral then oxidation state of Fe will be +2
If NO is positive then oxidation state of Fe will be +1

So EAN value will be same.

Hence correct answer is 0.