Step 1: Recall the use of transgenic animals:
Transgenic animals are made to produce valuable human proteins, usually in their milk.
Alpha-1-antitrypsin is a protein that protects the lungs from damage by enzymes. Its lack leads to emphysema, a lung disease.
Human alpha-1-antitrypsin is made in the milk of transgenic sheep and used to treat emphysema.
Step 2: Check the other options:
(A) Alpha-lactalbumin is a human milk protein made by transgenic cow Rosie. It is used to make milk nutritionally better for babies, not to treat emphysema.
(B) Thyroxine is a hormone made by the thyroid. It is not a transgenic animal product.
(D) Insulin is made by recombinant bacteria (E. coli) for diabetes.
Final Answer:
Option (C), alpha-1-antitrypsin.