Correct answer: A. Nonviolent fast and mediation
Explanation: The direct answer is A: Nonviolent fast and mediation. In the Ahmedabad mill workers’ dispute of 1918, workers demanded a wage increase after the plague bonus issue changed. Gandhi supported the workers and used satyagraha, including a fast, to create moral pressure while encouraging a settlement through mediation and arbitration. The reasoning is: labour dispute → workers’ demand → Gandhi avoids force → fast and negotiation/mediation → peaceful settlement process. Option A is correct because it describes the method associated with this struggle. Option B, armed attack, is wrong because Gandhi’s satyagraha rejected violence. Option C, help from a foreign army, is wrong because no foreign military intervention was the method. Option D, merger of princely states, is unrelated to a workers’ wage dispute and belongs to a different political issue. The fast was not a violent threat; it was intended as moral pressure and personal self-discipline. Memory cue: Ahmedabad 1918 means workers, wages, satyagraha, and fast.