Let's go through the reason for the correct answers:

A. Mahatma Gandhi was fighting against the apartheid system while he was in South Africa. - This statement is correct. Mahatma Gandhi spent a significant part of his early activism in South Africa, where he fought against racial discrimination and the apartheid system.

D. Chauri-Chaura incident occurred in 1922. - This statement is correct. The Chauri-Chaura incident was a violent event that took place in 1922, involving Indian protesters and the police. This incident played a role in Gandhi calling off the Non-Cooperation Movement.

The other statements are not correct for the following reasons:

B. After Gandhiji's return to India, his first public appearance and speech was in Champaran. - This statement is incorrect. After returning to India from South Africa, Gandhi's first major public appearance and speech were associated with the Champaran Satyagraha, but it wasn't his very first public appearance in India.

C. Rowlatt Satyagraha in 1922. - This statement is incorrect. The Rowlatt Satyagraha was a series of protests and agitations against the Rowlatt Act, which took place in 1919.

E. Civil Disobedience started in 1925. - This statement is incorrect. The Civil Disobedience Movement, led by Gandhi, started in 1930 with the famous Dandi March.

So, the correct answer is option 1: A, D only, as these are the statements that are factually accurate.