Which of the following statements is incorrect? (i) Insulin was originally extracted from pancreas of slaughtered pigs and cattle. (ii) Animal insulin is difficult to obtain. (iii) Animal insulin is identical to human insulin. (iv) Non human insulin caused some patients to develop allergy. (v) Recombinant DNA allowed scientists to insert a human insulin gene into a bacterial expression vector. (vi) Recombinant insulin is actually obtained from E. coli bacterial cell.

• A. (i) and (ii)       
• B.                    (iii) and (iv).
• C. Only (iii)     
• D.                    Only (vi)