The correct option is D Transgenic mice for testing safety of polio vaccine before use in humans
Transgenic mice are being used in testing the safety of vaccines before they are used on human beings. They are being used to test the safety of the polio vaccine.
The first transgenic cow, Rosie produced human protein enriched milk (2.4 gms per litre). The milk contained the human alpha-lactalbumin. It is a more balanced product for human babies than natural cow-milk.
Bulls with more power are produced by animal breeding not by genetic engineering.
So, the correct answer is 'Transgenic mice for testing safety of polio vaccine before use in humans'.