A major challenge to agriculture in Manipur is:

The correct answer is: All of the above.

Limited availability of arable land: Manipur is a mountainous state with a relatively small area of arable land. This is a major challenge to agriculture in the state, as it limits the amount of land that can be used for cultivation.

Lack of irrigation facilities: Manipur also suffers from a lack of irrigation facilities. This is a major problem, as it means that

Poor market access: Manipur is also a landlocked state, which means

All of these factors contribute to the challenges faced by agriculture in Manipur.