Explain how the understanding of atomic emission spectrum led to development of the atomic theory

It was Niels Henrik David Bohr, a Danish physicist, analyzed the atomic emission spectrum of hydrogen and showed mathematically that this was the result of movement of e- from a specific energy level to a lower energy level. This became the accepted theory that electrons could only be in specific locations and these locations corresponded to energy levels 1st energy level, 2nd energy level, etc.

The correct answer is d