निम्नलिखित में से कौन सा अंक किसी पूर्ण वर्ग संख्या का इकाई अंक नहीं हो सकता 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?