Terrace cultivation in Manipur is mainly practiced in:

Hilly regions
River valleys
Imphal East
Bishnupur District

The correct answer is: a) Hilly regions.

Terrace cultivation is a type of agriculture that is practiced on steep slopes. It involves building terraces on the hillsides to create level surfaces for growing crops. This type of cultivation is used in many parts of the world, including Manipur.

In Manipur, terrace cultivation is mainly practiced in the hilly regions of the state. The hilly regions are well-suited for terrace cultivation because they have a lot of rainfall and the soil is fertile. The terraces are built on the hillsides to create level surfaces for growing crops. This type of cultivation helps to prevent soil erosion and also helps to conserve water.

The other options are incorrect because:

  • Option b, River valleys, is incorrect because river valleys are not suitable for terrace cultivation. River valleys are usually flat and the soil is not as fertile as the soil in the hilly regions.
  • Option c, Imphal East, is incorrect because Imphal East is a district in Manipur. It is not a type of agriculture.
  • Option d, Bishnupur District, is incorrect because Bishnupur District is a district in Manipur. It is not a type of agriculture.