Explanation

Under the Mines and Minerals (Development and Regulation) Act, 1957 (MMDR Act), minerals are statutorily classified as either major minerals or minor minerals:

– Major Minerals: Minerals specified under central statutory governance. Chromite, Kyanite, and Sillimanite are categorized as major minerals, with regulatory leases and concessions handled under central frameworks.
– Minor Minerals: Under Section 3(e) of the Act, the Central Government has notified certain industrial clays and building minerals as minor minerals, transferring complete powers to frame rules to State Governments. Bentonite is officially designated and notified as a minor mineral.

Hence, minerals 2, 3, and 4 are major minerals — Option D.