Neils bohr believed that electrons orbited the nucleus in different energy levels, based on strong support from

the 3rd option for make sense,so that's out

Dalton was the pioneer behind the atomic model,but he certainly didn't believe in the nucleus or electrons,much lest electron shells.

Chadwick's discovery was the discovery of the neutron,not electron energy levels.

Niels Bohr's model was an attempt at explaining the hydrogen atom's spectrogram,followed by Erwin Schrödinger.Thus the first option is the answer

b. is the answer hoped i