Transgenic technology is a genetic operation at the molecular level. According to the pre-designed blueprint, the genes of one organism are separated, then transferred to another organism, cleverly spliced in vitro, and then transferred to another organism. Thereby transforming some genetic traits. Insect-resistant tobacco is a biotechnology that transfers the gene of Bacillus thuringiensis producing insecticidal toxin into the DNA of common tobacco. This gene-controlled trait is expressed in common tobacco to produce insecticidal toxin, which makes tobacco have good insect-resistant effect. This tobacco is called transgenic insect-resistant tobacco. Therefore, using genetic engineering to cultivate insect-resistant tobacco.

So choose: B.