The number of solutions of the equation \( 2x + 3 \tan x = \pi \), \( x \in [ -2\pi, 2\pi ] - \left\{ \pm \frac{\pi}{2}, \pm \frac{3\pi}{2} \right\} \), is:
\( 5 \)
\( 6 \)
\( 3 \)
\( 4 \)