Bollgard I and Bollgard II technologies are mentioned in the context of ​

Bollgard I and Bollgard II are Monsanto's Bt cotton technologies, so the answer is B: developing genetically modified crop plants.

A gene from the soil bacterium Bacillus thuringiensis is inserted into the cotton plant. The plant then produces its own Cry protein, which is toxic to bollworm larvae. Bollgard I carries one Cry gene (Cry1Ac). Bollgard II stacks two (Cry1Ac and Cry2Ab) to delay pest resistance. India approved Bt cotton in 2002, and the GEAC regulates such releases.

• A (clonal propagation): this is tissue culture, which multiplies identical plants from explants. Bollgard has no role there.
• C (plant growth substances): auxins and gibberellins are growth substances. The Bt protein is an insecticidal protein, not a growth regulator.
• D (biofertilizers): Rhizobium, Azotobacter and phosphate-solubilising bacteria are biofertilizers. Bollgard is a pest-control trait.

Core concept: transgenic crops and Bt technology. This links to the GM crops debate, biosafety regulation and the status of GM food crops in India, a recurring Mains theme.

Trap: candidates sometimes confuse any biotech term with tissue culture or biofertilizers. Ask first whether the product is a plant, a microbe or a growth hormone.