Wish of the following BEST describes an orbital?

a
According to the Bohr model of the atom, it is a three dimensional region of space where there is a 90% probability of finding a neutron at any given moment in time.
b
According to the Bohr model of the atom, it is a three dimensional region of space where electrons are constantly found.
c
According to the quantum mechanical model of the atom, it is a three dimensional region of space where protons are constantly found
d
According to the quantum mechanical model of the atom, it is a three dimensional region of space where there is a 90% probability of finding an electron at any given moment in time.

b/c the bohr atomic model say that the electron are present in the orbits where the modern physics suggests that according to hisenberg uncertainity principle u cannot locate an electron but can find its maximum probibility in a given region and that is named as orbital

Answer Link