The correct answer is $\boxed{\text{C}}$.
The magnetic quantum number, $m_l$, determines the orientation of an electron’s orbital in an atom’s magnetic field. It can have values from $-l$ to $l$, inclusive, where $l$ is the orbital angular momentum quantum number. The maximum value of $m_l$ is equal to $l$ when the orbital is spherically symmetric.
In an orbit with maximum magnetic quantum number, $m_l = +3$, the electron can only make two waves. This is because the electron must be in a spherically symmetric orbital, and there are only two possible orientations for a spherically symmetric orbital in a magnetic field.
The other options are incorrect because they do not correspond to the maximum value of $m_l$ for an electron in an orbit. Option A, $4$, is incorrect because the maximum value of $m_l$ is $l$, which is equal to $3$ in this case. Option B, $5$, is incorrect because there are only two possible orientations for a spherically symmetric orbital in a magnetic field. Option D, $0$, is incorrect because the electron must be in a spherically symmetric orbital, and there are always two possible orientations for a spherically symmetric orbital in a magnetic field.