The dependence of binding energy per nucleon, B_N on the mass number A , is represented by

Step-by-step solution

The graph showing that greater the binding energy per nucleon, the more stable the nucleus is. The graph has its maximum of 8.8 MeV / nucleon when the number of nucleons is 56 . The nucleus that has 56 protons and neutron is ₂₆⁵⁶ Fe , an iron isotope. This is the most stable nucleus of them all, since maximum energy is needed to pull a nucleon away from it.