Out of the given options, the charge of an electron was not contributed by Neils Bohr.
Answer: Option 2
Explanation:
The electron's charge was determined by using oil drop experiments performed by Millikan. While Neil Bohr suggested that electrons are rotating in discrete energy levels termed as orbits.
The hydrogen model of Neil Bohr dealt with the quantum energy emission when electron excite from higher energy level to lower energy level. He also stated that there is a relationship between the outer shell and the chemical properties of elements.
So, the second option that is the charge of an electron is not contributed by Bohr as it was contributed by Millikan.