Section 3(d) Patents Act 1970, as inserted by the 2005 amendment, excludes from patentability:

1. Section 3(d) Patents Act 1970 (as substituted by the Patents (Amendment) Act, 2005) excludes from 'invention' the mere discovery of a new form of a known substance which does not result in the ENHANCEMENT OF THE KNOWN EFFICACY of that substance, or the mere discovery of any new property or new use for a known substance, or of the mere use of a known process, machine or apparatus unless such known process results in a new product or employs at least one new reactant. 2. The Explanation provides that for the purposes of this clause, salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations and other derivatives of known substance shall be considered to be the same substance, UNLESS they differ significantly in properties with regard to efficacy. 3. Novartis v. UoI (2013) — Supreme Court denied patent to Glivec (Imatinib Mesylate) and interpreted 'efficacy' as 'therapeutic efficacy' for medicines. 4. Hence option B is correct. _Source: Patents Act 1970 / Copyright Act 1957 / Trade Marks Act 1999 (Bare Acts, IPIndia portal + Copyright Office) — Patents Act 1970, Section 3(d); Novartis AG v. Union of India, (2013) 6 SCC 1_