'खेजड़ी' को किस वर्ष राजस्थान का राज्य वृक्ष घोषित किया गया था?

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?