Question

Two electrons occupying an orbital are distinguished by
A. Principle quantum number
B. Angular momentum quantum number
C. Magnetic quantum number
D. Spin quantum number

Answer 1

We generally know about the four types of quantum numbers.
They are principal, azimuthal, magnetic, and spin quantum numbers.
Values of these quantum numbers depend on the position, shape, or direction of the electrons and orbitals.

Complete step by step solution:
We know a quantum number is a group of numbers used to define the position and energy of an electron in an atom. The principal quantum number is denoted by and, azimuthal is which is called an orbital angular momentum quantum number .magnetic by and spin by
The electron shell or energy level, of an electron, is described by the principal quantum number. The $n$ ranges from the $1$ to outermost electron
$n\; = {\text{ }}1,{\text{ }}2,{\text{ }}...$
The azimuthal quantum number, known as the angular quantum number or orbital quantum number, defined the subshell, and it gives the magnitude of the orbital angular momentum,
The magnetic quantum number is defined as the specific orbital or "cloud" within that subshell, and gives the projection of the orbital angular momentum along a specified axis:
The spin quantum number defined about the intrinsic spin angular momentum of the electron within each orbital and gives the projection of the spin angular momentum $S$ along the specified axis:
The spin quantum number distinguishes these two electrons are in the same orbits hence the right answer is in option (D).

Note:
The principal quantum number builds upon the distance between the electron and nucleus.
The azimuthal quantum number depends on the shape of the orbital
The magnetic quantum number depends on the number of the orientation of orbits
The spin quantum number depends on the direction of the electron spinning.