Correct answer: D. Because he organised peasants in a disciplined manner
Explanation: Direct answer: Option D is correct. In the Bardoli Satyagraha of 1928 in Gujarat, the colonial government increased land revenue. Vallabhbhai Patel led the peasants against this increase. He helped them remain united, disciplined, peaceful, and firm despite pressure, confiscation, and official action. The successful organisation and leadership impressed the people, and women of Bardoli gave Patel the title “Sardar,” meaning leader or chief. Option D captures the reason for this image. Option A is wrong because INA trials belonged to the post-Second World War period and were not the cause of Patel’s Bardoli title. Option B is wrong because the Chipko Movement was a later forest-protection movement associated with Himalayan villagers. Option C is wrong because Nil Darpan was a play by Dinabandhu Mitra about indigo cultivation and oppression, not Patel’s work at Bardoli. The fact chain is: 1928, Bardoli in Gujarat, revenue increase, peasant resistance, Patel’s disciplined leadership, title Sardar. Memory cue: “Bardoli–1928–revenue–peasants–Sardar Patel.”