Consider the following minerals : 1. Bentonite 2. Chromite 3. Kyanite 4. Sillimanite In India, which of the above is/are officially designated as major minerals ?

Option (d) is correct because Chromite, Kyanite, and Sillimanite are classified as major minerals under the Mines and Minerals (Development and Regulation) Act, 1957. Bentonite is officially designated as a "minor mineral," which makes options (a) and (c) incorrect as they include it in the major minerals category. The core concept tested is the statutory classification of minerals in India and the ability to distinguish between major and minor minerals based on government notifications.