The correct options are
C Extraction of Animal insulin is very expensive
D The amount of insulin extracted from a single animal was not sufficient to meet the demand of insulin
Everyday several animals, specifically pigs, had to be scarificed for the extraction of insulin from these animals since it was not possible to extract insulin from live animals. Along with the fact that the amount of insulin obtained from a single animal is very less, the price of Insulin became extremely expensive for those who were not economically well off.