Option (c) is the correct answer because the first transgenic cow Rosie produced human protein-enriched milk. The milk contained the human alpha-lactalbumin and was nutritionally a more balanced product for human babies than natural cow milk.

Option (a) is not the correct answer because ADA deficiency in humans can be cured by gene therapy.

Option (b) is not the correct answer because transgenic sheep produced human $\alpha$-1-antitrypsin that is used to treat emphysema.

Option (d) is not the correct answer because insulin-like growth factor was not present in Rosie’s milk.