The following list contains some stages in the production of human insulin by genetic engineering. 1. The human insulin gene is added to a bacterial plasmid with DNA ligase. 2. A recombinant plasmid is placed into a bacterium. 3. The bacterium carrying the recombinant plasmid multiplies. 4. The insulin gene is cut out of human DNA using a restriction enzyme. What is the correct order of these stages?
- A1 → 2 → 4 → 3
- B2 → 4 → 3 → 1
- C3 → 2 → 1 → 4
- D4 → 1 → 2 → 3