In the simple model of an atom, protons, neutrons and electrons are present. Which class (group) do these particles belong to: hadron or lepton?
- Ahadron: electron; lepton: proton and neutron
- Bhadron: neutron; lepton: proton and electron
- Chadron: proton and electron; lepton: neutron
- Dhadron: proton and neutron; lepton: electron