Which one of the following is wrong?

In 1997, the first transgenic cow, Rosie, produced human alpha-lactalbumin enriched milk at 2.4 grams per litre. This transgenic milk is a more nutritionally balanced product than natural bovine milk and could be given to babies or the elderly with special nutritional or digestive needs. Restriction enzymes are DNA-cutting enzymes found in bacteria (and harvested from them for use). Because they cut within the molecule, they are often called restriction endonucleases. They are not used for isolation of DNA. Downstream processing refers to the recovery and purification of biosynthetic products, particularly pharmaceuticals, from natural sources such as animal or plant tissue or fermentation broth, including the recycling of salvageable components and the proper treatment and disposal of waste. Downstream processing is usually considered a specialized field in biochemical engineering. Pathogens like the bacteriophage vectors are disarmed and allowed to infect the bacterial cells. They transfer the rDNA into the host. Hence, the correct option is D.