The double membrane around the nucleus is called the

C. nuclear envelope

Explanation:

The nucleus is surrounded by a double membrane, known as the nuclear envelope, with nuclear pores. Mitochondria - this is the site of aerobic respiration within the cell. They are surrounded by a double membrane (envelope), with the inner membrane folded into finger-like projections called cristae.

the last one: artificial selection/genetic engineering

plant breeding is modifying the genetic composition of the plant - but this isn't cloning (which is specifically introducing a gene into a genome). but you are artificially selecting for the phenotype that you want.

the second one is literally genetic engineering - the gene would have been cloned first and then inserted or genetically engineered into the new plant cell (the cotton).