Which is oxidation state of iron in haemoglobin?

Haemoglobin is an oxygen transporting pigment in RBC.

It is made up of two parts, a prosthetic group and a protein part.

Prosthetic group contains iron in its center.

Iron is present in Fe²⁺ stage to coordinate well with oxygen.

The correct answer is Option B, iron is present as Fe²⁺ in haemoglobin, because in rest three states of iron it does not coordinate well with oxygen.