Concept:
Magnetic quantum number ($m_l$) depends on azimuthal quantum number ($l$):
\[
m_l = -l \text{ to } +l
\]
Step 1: For p-orbital.
\[
l = 1
\]
Step 2: Possible values of $m_l$.
\[
m_l = -1, 0, +1
\]
Step 3: Count values.
\[
\text{Total} = 3
\]
Step 4: Conclusion.
Thus, there are 3 possible values.
Final Answer: Option (B)