Answer:
The correct answer is bacteria
Explanation:
Earlier insulin was taken out from the animals like pigs and cows but in 1978 first artificial insulin was produced by using E.coli bacteria. Elli Lilly was the first company who synthesized and sell synthetic human insulin.
They inserted the gene which codes for human insulin peptide in E.coli. The two different peptides of insulin were synthesized separately in E.coli and they were joined by a disulfide bond later to produce active synthetic human insulin. So now insulin is obtained from bacteria.