The Department for Promotion of Industry and Internal Trade (DPIIT) has revised the base year index of Eight Core Industries, which have a combined weight of about 40.27 percent in the Index of Industrial Production. This means that the performance of these industries has a significant impact on the overall industrial production in the country.

The Eight Core Industries, which are considered to be the backbone of the industrial sector, include coal, refinery products, cement, and several others. The correct answer is option 3, rubber products, as it is not one of the Eight Core Industries.

Coal, as a core industry, is vital for the energy sector and plays a major role in electricity generation and the production of steel. Refinery products, on the other hand, include petroleum products such as diesel, gasoline, and jet fuel. These products are essential for various sectors such as transportation, manufacturing, and agriculture.

Cement is a key ingredient in the construction industry and is used in the production of buildings, roads, and infrastructure. Therefore, it is an important component of the Eight Core Industries.

In conclusion, while coal, refinery products, and cement are part of the Eight Core Industries, rubber products are not included in this category.