The Advantage of Being Able to Clone the Gene for Human

The advantage of being able to clone the gene for human insulin is that

A) cow,pig,or horse insulin cannot keep a diabetic alive for more than three months.
B) human insulin is less likely to cause harmful side effects than cow,pig,or horse insulin.
C) using human insulin increases the probability that,in the future,the person suffering from diabetes can be weaned from a dependence on insulin.
D) there are too few cows,pigs,and horses to provide an adequate supply of their insulin.