Consider the following statements. (i)In earlier days insulin extracted from pancreas of slaughtered cattle and pigs, was more efficient than genetically engineered insulin. (ii) PCR technique is being used for the detection of HIV and genetic mutations, in suspected cancer patients. (iii) Cystic fibrosis, heamophilia, cancer, Parkinson's etc., are treated by gene therapy. Which of the statements given above are correct?

• A. (i) and (ii)                                  
• B. (i) and (iii)
• C. (ii) and (iii)
• D. (i), (ii) and (iii)