The correct answer is: b) Significant among tribal communities.
The Non-Cooperation Movement was a major political movement in India that was launched in 1920 by Mahatma Gandhi. The movement was aimed at achieving swaraj, or self-rule, for India. The movement was significant among tribal communities in Meghalaya because it provided them with an opportunity to assert their rights and to demand a greater say in the affairs of their own communities. The movement also helped to raise awareness of the problems faced by tribal communities and to bring about some positive changes in their lives.
Option a) is incorrect because the Non-Cooperation Movement was not limited to urban centers. It was also popular in rural areas, including in tribal areas.
Option c) is incorrect because the Non-Cooperation Movement was not focused on economic boycotts. It was a much broader movement that involved a variety of activities, including protests, strikes, and boycotts.
Option d) is incorrect because the Non-Cooperation Movement was not supported by missionaries. In fact, some missionaries were opposed to the movement because they felt that it was too radical.