i only need question 4 thank you

We consider the binuclear complex depicted below where A and B are paramagnetic transition metal ions with spin values SA and Sg respectively; O is the O2 bridging the metal ions. 3- Assume that A = B = Cu", give the electronic configuration of Cu". 4- Give the lift of degeneracy of the d orbitals knowing that the Cu" ions are in a square-planar environment. Perform an electronic filling of orbitals d. Deduce the values of SA and Se. 5- Give the total spin values S obtained by coupling the SA and Se spins