In India, the steel production industry requires the import of

1. A

   saltpetre

   Saltpetre is potassium nitrate, used historically in gunpowder and in some fertilisers. It is not a feedstock the Indian steel industry must import. This option is not the key.

2. B

   rock phosphate

   Rock phosphate is a fertiliser raw material. Steelmaking does not rest on imported rock phosphate. This option is therefore wrong.

3. C

   coking coal

   Indian blast-furnace steel needs metallurgical (coking) coal to make coke. Domestic coking-coal quantity and quality are inadequate, so the industry imports coking coal. This option is the official key.

4. D

   All of the above

   All of the above would be true only if saltpetre and rock phosphate were also steel-import needs. They are not. This option is not the key.

Summary. Official key is (c) coking coal. Integrated steel plants depend on coke from coking coal, which India imports in large volume. Saltpetre and rock phosphate belong to explosives and fertiliser chemistry, not to the steel import basket asked here. ‘All of the above’ therefore fails. Only coking coal matches the industry’s import requirement.