Explanation:

- Option 1 - Gold:

- The Chota Nagpur Plateau is not known for gold mining.

- Gold deposits in India are primarily found in Karnataka and Andhra Pradesh.

- Gold is NOT a significant mineral found in the Chota Nagpur belt.

- Option 2 - Iron-ore:

- The Chota Nagpur Plateau is rich in iron ore.

- It is a key mining region for iron in India.

- Option 3 - Chromite:

- Chromite is another mineral found in this region.

- Not as abundantly mined as iron ore, but present.

- Option 4 - Coal:

- This region has significant coal deposits.

- It is one of the major coal-producing areas of India.