What can be considered the greatest achievement of the Non-Cooperation Movement?

Correct answer: It turned the national movement into a mass movement

The major historical achievement of Non-Cooperation was the widening of political participation. Students, teachers, lawyers, merchants, peasants, workers, and women joined through boycotts, demonstrations, national institutions, or local action. It did not immediately end colonial rule, abolish the tax system, or transfer the army to Indian control. Hence option A is correct because the movement transformed nationalism from a limited political activity into a broad mass struggle.