The Simon Commission arrived in India in 1928, sparking nationwide protests. Gandhi launched the Dandi March (Salt Satyagraha) in 1930. The Gandhi-Irwin Pact was signed in March 1931, temporarily suspending the civil disobedience movement. The Poona Pact between Gandhi and Ambedkar was signed in September 1932, replacing separate electorates for Dalits with reserved seats. Thus the correct sequence is 2-1-4-3.