Step 1: Understanding the problem.
Teenage substance abuse is a serious social and health issue requiring preventive, corrective, and rehabilitative actions.
Step 2: Evaluating each course of action.
(a) Stricter laws — acts as a deterrent, addresses the legal side.
(b) Awareness programs — preventive measure by educating about consequences.
(c) Random drug tests — invasive, possible ethical/legal issues, not the most effective alone.
(d) Rehabilitation centers — corrective action to help affected teenagers recover.
Step 3: Conclusion.
A combined approach of prevention (b), deterrence (a), and rehabilitation (d) is most effective.
\[
{\text{Implement (a), (b), and (d) together for maximum effectiveness.}}
\]