AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
(C) Copper smelting
According to the textbook, basic or key industries supply their products as raw materials to manufacture other goods — examples given are iron and steel, copper smelting, and aluminium smelting.
Source: Classification of Industries, Chapter 6
---
The question tests the definition of basic/key industries — those whose output serves as raw material for other industries. From the options given, copper smelting is the correct answer as it is explicitly listed as a basic industry in the textbook. Sugar, toothpaste, and sewing machines are listed as consumer industries. Always link the answer back to the textbook definition.