The correct answer is: b) Burma
Trade and cultural exchange in Manipur’s medieval period flourished with regions like Burma. This is evident from the fact that there are many similarities between the cultures of Manipur and Burma, such as the use of the same language, the practice of the same religion, and the celebration of the same festivals. In addition, there is evidence of trade between the two regions, such as the discovery of Burmese coins in Manipur.
Option a) China is incorrect because there is no evidence of significant trade or cultural exchange between Manipur and China during the medieval period.
Option c) Assam is incorrect because there is evidence of some trade and cultural exchange between Manipur and Assam during the medieval period, but it was not as significant as the trade and cultural exchange between Manipur and Burma.
Option d) Bengal is incorrect because there is no evidence of significant trade or cultural exchange between Manipur and Bengal during the medieval period.