The correct answer is: b) Medium-grade
Coal is a fossil fuel formed from the remains of ancient plants and animals that have been buried and subjected to intense heat and pressure over millions of years. It is a non-renewable resource that is used to generate electricity, produce steel, and make other products.
The quality of coal is determined by its carbon content, volatile matter content, ash content, and sulfur content. High-grade coal has a high carbon content, low volatile matter content, low ash content, and low sulfur content. Low-grade coal has a low carbon content, high volatile matter content, high ash content, and high sulfur content.
The coal found in Arunachal Pradesh is generally medium-grade. It has a carbon content of about 60%, a volatile matter content of about 30%, an ash content of about 10%, and a sulfur content of about 1%.
Medium-grade coal is a good quality coal that can be used to generate electricity, produce steel, and make other products. It is not as good as high-grade coal, but it is better than low-grade coal.
The other options are incorrect because they do not accurately describe the quality of coal found in Arunachal Pradesh.
Option a) is incorrect because it states that the quality of coal found in Arunachal Pradesh is high-grade. This is not accurate because the coal found in Arunachal Pradesh is generally medium-grade.
Option c) is incorrect because it states that the quality of coal found in Arunachal Pradesh is low-grade. This is not accurate because the coal found in Arunachal Pradesh is generally medium-grade.
Option d) is incorrect because it states that the quality of coal found in Arunachal Pradesh is extremely poor quality. This is not accurate because the coal found in Arunachal Pradesh is generally medium-grade.