For an electron with angular (azimuthal) quantum number ℓ = 2, the magnetic quantum number m can have

-2, -1, 0, +1, +2

Explanation:

The quantum numbers describe the quantum state of an electron in an atom. These numbers are symbolized as n, l, m, and s. There are rules for the combination of these numbers. The angular quantum number (ℓ) is related to the magnetic number (m): if ℓ is equal to a number a, thus m can be any integer number between - a and +a.

According to this rule:

If ℓ = 2, thus m can be have a value of an integer between -2 and +2 ⇒ -2, -1, 0, +1, +2