Mahatma Gandhi gave up the title of Kaiser-i-Hind and returned all the war medals which were awarded to him by the British for his war services (during the First World War)

Solution(By Examveda Team)

Mahatma Gandhi gave up the title of Kaiser-i-Hind and returned all the war medals awarded to him by the British for his war services during the First World War as a symbolic gesture of protest and solidarity with the Khilafat Movement. The Khilafat Movement was initiated to support the cause of the Ottoman Caliphate (Caliphate of Turkey) after the end of World War I.

Option A: Mahatma Gandhi's decision to return the war medals was not directly related to the Jallianwala Bagh tragedy, which occurred in 1919.
Option B: The Non-Cooperation Movement, initiated by Gandhi, aimed at boycotting British institutions, including educational institutions and government services. It began in 1920, but the return of war medals was specifically related to the Khilafat Movement.
Option D: The Champaran Satyagraha was one of Gandhi's early movements in India against the exploitation of indigo farmers in Champaran, Bihar. The return of war medals was not associated with this movement.

Therefore, the correct option is Option C: in support of the Khilafat demand when the Central Khilafat Committee organised a general all-India hartal on August 1, 1920, as Mahatma Gandhi returned the war medals and gave up the title of Kaiser-i-Hind as part of his support for the Khilafat Movement.