The correct answer is D. Lala Lajpat Rai died during the protest of Simon commission.
The Simon Commission was a British parliamentary commission that was appointed in November 1927 to review the working of the Government of India Act 1919. The commission was all-white, and this led to widespread protests in India. Lala Lajpat Rai was one of the leaders of these protests, and he was killed by police during a protest in Lahore on 30 October 1928.
The other options are all correct. The activities of the Swaraj Party had induced the British Government to review the working of the diarchy system introduced by the Montague-Chelmsford reforms. The British Government appointed the Simon Commission in November 1927. The Simon Commission was opposed because it was all-white.
The Simon Commission was a major turning point in the history of India. It led to the rise of the Indian National Congress and the demand for independence.