Answer:
The correct set of values of m for one of the subshells is -1,0,1.
Step-by-step explanation:
The "Principal quantum number" (n) represents the number of shells (levels) that an atom has where the electrons has the higher probability to be find.
The "Magnetic quantum number" (m) represents the orientation of the electrons in a subshell (s, p, d, f). The number it takes depends on the location of the electron in that subshell.
Remeber that each shell (level) has specific subshells and a specific number of electrons to be placed. For example, shell number 1 has only s subshell, shell number 2 has s subshell and p subshell, shell number 3 has s, p and d subshells and so on (you can check this in a Moeller's Diagram).
In this case, the principal quantum number n is 2, so it has the s subshell and the p subshell. You can see this in the attachment.
S subshell has only 1 orbital (space for two electrons), that means that the electrons on it have only one type of orientation, that's why the magnetic quantum number can be equal 0.
P subshell has 3 orbitals (space for six electrons), that means that the electrons on it could have 3 types of orientation and that's why the magnetic quantum number could be -1, 0 or 1 depending on where orbital the electrons are placed.
So, for n=2, the magnetic quantum number has the value 0 for the s subshell, and it has the set of values -1,0,1 for the p subshell.