Explanation:

- The 'Eight Core Industries' of India comprise sectors that are fundamental to the economy's infrastructure.

- Option 1: Fertilizers

- Fertilizers are part of the core industries and play a crucial role in agriculture.

- Option 2: Steel

- Steel is included in the core industries, as it is essential for construction and manufacturing.

- Option 3: Cotton

- Cotton is NOT part of the Eight Core Industries. It is crucial for textiles but not included in the core sectors.

- Option 4: Natural Gas

- Natural Gas is a core industry and important for energy production.

Correct Answer: Option 3 - Cotton

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