Explanation:

- MSP: Minimum Support Price

- It assures farmers that their produce will be purchased by the government at a pre-determined price.

- Acts as a safety net for farmers to prevent exploitation by middlemen.

- CACP: Commission for Agricultural Costs and Prices

- A body that recommends the level of MSP to the government.

- It takes into account various factors including cost of production and market trends.

- NABARD: National Bank for Agriculture and Rural Development

- Focuses on providing financial support for rural development.

- It is not directly related to purchasing produce from farmers.

- PDS: Public Distribution System

- A government program to distribute food grains at subsidized rates to the poor.

- It is more about distribution rather than purchasing produce at a fixed price.