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