कौन सा ऐतिहासिक संदर्भ मुख्य रूप से जॉन बार्थ के उपन्यास 'द फ्लोटिंग ओपेरा' की पृष्ठभूमि को प्रभावित करता है?

The 'Drain of Wealth' theory was propounded by which Indian nationalist leader?

Which event is considered the turning point in Mahatma Gandhi's leadership in the Indian independence movement?

Which African leader is known for his non-violent opposition to colonial rule?