Step 1: Understanding Gandhian philosophy.
Gandhian philosophy centers on non-violence, truth, and the pursuit of social and political freedom. Key principles include: - Non-violence and Satyagraha are fundamental, advocating for peaceful resistance. - Swaraj, or self-rule, was crucial to India's independence movement. - While the Annihilation of Caste was a significant societal issue, it was primarily addressed by Dr. B.R. Ambedkar rather than Gandhi.
Step 2: Conclusion. The correct option is 3. Annihilation of Caste.
Final Answer: \[ \boxed{\text{The correct answer is 3. Annihilation of Caste.}} \]