Which of the following was the most important feature of the Montague-Chelmsford reforms?

Dyarchy, also spelled diarchy, system of double government introduced by the Government of India Act (1919) for the provinces of British India. Dyarchy was introduced as a constitutional reform by Edwin Samuel Montagu (secretary of state for India, 1917–22) and Lord Chelmsford (viceroy of India, 1916–21).