Answer:
Correct option: D (both A and B)
Explanation:
Key things of bohr's model is that electrons occupy fixed orbital and required fixed amount of energy and electron must be in specific orbital and have precise amount of energy for that orbit
Niels bohr proposed a hydrogen atom model which explains the spectrum of hydrogen and he assumed that electron of hydrogen revolves around the nucleus in the circular orbit and bohr's model is valid only for single electron species.
statement of option A and B are correct
hence D is correct