Plz answer ,question no. 88 with explanation

Dear student. The configuration of the ions is shown below - a) Fe(ground state) - 3d64s2, Fe3+ion is thus 3d5. b) Cr(ground state) - 3d54s1, Cr3+ ion is thus 3d3. c) Mn(ground state) - 3d54s2, Mn2+ thus becomes 3d5. d) Co is, 3d74s2, Co3+ ion thus becomes 3d6. e) Ni is 3d84s2, Ni2+ thus becomes 3d8. So, Fe3+ and Mn2+, have same configuration. Option B is correct. Regards