Assertion (A) : Lord Linlithgo described the August Movement of 1942 as the most serious revolt after the Sepoy mutiny. Reason (R) : Peasants joined the movement in large number in some places.

Assertion is true: Viceroy Linlithgow characterised the August (Quit India) movement as an exceptionally serious internal disturbance, i.e. comparable to the 1857 upheaval. The Reason is also true: the movement was a genuine mass upsurge that included large numbers of ordinary Indians and peasants, with strikes, sabotage and even the formation of “independent” or parallel authorities in districts such as Satara and Medinipur; the campaign therefore involved broad rural participation in several areas [1]. Peasant mobilisation in particular amplified the scale and intensity of the unrest and helps explain why the administration regarded August 1942 as so grave, so R correctly explains A.

Sources

1. [1] THEMES IN INDIAN HISTORY PART III, History CLASS XII (NCERT 2025 ed.) > Chapter 11: MAHATMA GANDHI AND THE NATIONALIST MOVEMENT > 4. Quit India > p. 303
2. [2] https://ia601500.us.archive.org/22/items/in.ernet.dli.2015.220430/2015.220430.The-Indian_text.pdf