Step 1: Use the given equation.
We are given the equation:
\[
\tan 3\theta \cdot \tan 2\theta \cdot \tan \theta + \tan 2\theta + \tan \theta = 1
\]
By solving the equation, we find that \( \theta = \frac{\pi}{12} \).
Step 2: Conclusion.
Thus, the value of \( \theta \) is \( \frac{\pi}{12} \), corresponding to option (A).