The correct options are
A To establish a united Hindu-Muslim front
C To counter the effect of British policies which were increasing communal divisions
The Khilafat movement began in India as a way of protesting the dismemberment of the Ottoman Caliphate. Gandhi's support to the movement was a strategy to counter the Divde-and-Rule policies of the colonial government and ensure communal harmony. He wanted to bring Hindus and Muslims together in the fight against the British. The Muslims thus whole-heartedly participated in the Non-cooperation Movement, launching a united attack against the Raj.