What was the name of the American biographer of Gandhiji?

The correct answer is Option 2 - Louis Fischer

Mahatma Gandhi’s American biographer was Louis Fischer.

“Non-cooperation,” wrote Mahatma Gandhi’s American biographer Louis Fischer, “became the name of an epoch in the life of India and of Gandhiji. Non-cooperation was negative enough to be peaceful but positive enough to be effective. It entailed denial, renunciation, and self-discipline. It was training for self-rule.” As a consequence of the Non-Cooperation Movement the British Raj was shaken to its foundations for the first time since the Revolt of 1857.