Read the following passage carefully and answer the questions given below:
Coal is a natural resource which constitutes approximately 85 percent of the total fossil fuel reserves in the world. The coal deposits of India occur in two distinct stratigraphic horizons: Gondwana and its territories. Gondwana coal contributes about 99% of the country's coal resources. These mines are located in peninsular India, in the South Eastern quadrant, bound by the 78°E longitude and the 24°N latitude, thus, leaving a major part of the country devoid of any coal deposits. The major Gondwana coalfields are represented by isolated basins, which occur along prominent present day rivers such as Damodar, Koel, Sone, Mahanadi, Pench and Godavari. The relatively minor resource of tertiary coal is located on the either extremities of peninsular India.
Coal can be broadly classified in two categories - coking and non-coking. Coking coal are those which have cacking property and which is used in metallurgical industries. Again depending on the quality of coke produced by this coal, it is sub-divided into prime coking coal, medium coking coal, and semi-coking coal. Similarly, non-coking coal is also categorized in seven grades (Grade A to G), depending on its caloric value.