It is denoted by \(m_l\).

It gives information about the spatial orientation of the orbital with respect to the standard set of co-ordinate axis.

The explanation for the incorrect option

Azimuthal quantum numbers tell about the shape of the orbital.

The spin quantum number denotes the orientation of the spin of the electron.

The principal quantum number determines the size and to large extent the energy of the orbital.

So, options \((A), (B)\) and \((D)\) are incorrect.

Hence, option \((C)\) is correct. The orientation of an atomic orbital is governed by magnetic quantum numbers.