निम्नलिखित में से किसका प्रतिरोधकता का तापमान गुणांक ऋणात्मक (negative temperature coefficient of resistivity) होता 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?