What did Bohr conclude about the atom after observing emission spectrum lines a. Electrons can exist in any energy state but have specific states that are preferred. b. No two electrons can exist in the same quantum state within an atom. c. Possible electron energy states are quantized within an atom. d. Plum pudding tastes fantastic.

Option c: Possible electron energy states are quantized within an atom.

Explanation:

The Bohr's Model of the hydrogen atom consisted of the movements of the electrons around the positively-charged nucleus in circular orbits that have a certain energy state. The energy of that orbit is given by:  

Where:

E(n): is the energy of an electron in a particular orbit

R: is the Rydberg constant

h: is the Plank constant

c: is the speed of light

n: is a positive integer which corresponds to the number of the orbit

The ground state energy of a electron in the hydrogen atom is equal to -13,6 eV.

Bohr's Model aims to propose that the electron is restrictedly to occupy a certain region in the atom.    

Therefore, the conclusion of Bohr after observing emission spectrum lines is that "possible electron energy states are quantized within an atom", so the correct option is c.

I hope it helps you!

it is the most commonly accepted one