Several stages in the manufacture of human insulin are given below. 1. Genetically modified E. coli bacteria are cultivated in large fermenters. 2. The gene for human insulin is placed into the DNA of an E. coli bacterium. 3. The gene for human insulin is taken from human pancreas cells. 4. Human insulin is removed and purified. Which sequence of stages is correct?
- A3 → 1 → 2 → 4
- B4 → 3 → 2 → 1
- C3 → 2 → 4 → 1
- D3 → 2 → 1 → 4