The correct option is A Simon Commission
The Simon Commission was appointed in 1927 by the British government to study the Constitutional reforms in India. The Government of India Act, 1919 introduced Diarchy which was opposed by Indian people, the Act itself provided for investigation after 10 years by a commission. This Commission consisted of seven British members of Parliament and was firmly opposed by Indians because of no Indian in commission deciding upon the fate of India. The report of commission brought about the Government of India Act,1935 which abolished dyarchy and created provincial autonomy.