Assertion (A): Lord Linlithgow described the August Movement of 1942 as the most serious rebellion since Sepoy Mutiny. Reason (R): There was massive upsurge of the peasantry in certain areas.

The correct answer is A because both statements are historically accurate and the reason directly explains the assertion. The assertion is true because Lord Linlithgow, the then Viceroy of India, wrote a personal letter to Winston Churchill describing the Quit India Movement also known as the August Movement as the most serious rebellion since 1857. This was due to the widespread violence and the total breakdown of British authority in several districts. The reason is true and provides the correct explanation because the intensity of the movement was driven by a massive and violent upsurge of the peasantry. In regions like Bihar, Eastern Uttar Pradesh, Bengal, and Maharashtra, peasants attacked police stations, post offices, and railway lines. This large scale rural participation transformed a political protest into a formidable armed rebellion, leading Linlithgow to compare its severity to the 1857 Mutiny.