कीटकांच्या आक्रमणाला प्रभावीपणे तोंड देणारी बी.टी. कॉटन ही एक _____ प्रकारची कपाशीची जात आहे.

The correct answer is Option B (Genetically modified).

Key Points:
• Recombinant DNA Technology in Agriculture:
• Bt Cotton is a transgenic, Genetically Modified (GM) crop approved for commercial cultivation in India in 2002 by the Genetic Engineering Appraisal Committee (GEAC).
• Biotechnology Mechanism:
• Gene sequences (*Cry1Ac* and *Cry2Ab*) were isolated from the common soil bacterium *Bacillus thuringiensis* (Bt) and inserted into the cotton genome.
• The transformed plant produces endogenous crystalline endotoxin (Cry protein) in its tissues.
• When pests such as the cotton bollworm (*Helicoverpa armigera*) ingest plant tissue, alkaline gut fluids solubilize the toxin, creating pores that destroy intestinal epithelial cells and neutralize the pest.
• Hence, Bt cotton is a Genetically modified crop (Option 2).
• Key Takeaway: Bt cotton is a genetically modified (transgenic) crop incorporating bacterial Cry genes to confer resistance against bollworm pests.