A、The shortage of willing donors. B、The obtaining of moral approval. C、The complex technical procedure. D、The rejection from the

Full face transplants are no longer science fiction fantasy, a leading surgeon has said, adding that they are technically feasible but morally complex. Peter Butler from London’s Royal Free Hospital called for a debate on the morality of such an operation made possible by new drugs which stop the body’s immune system rejecting a transplanted face. "It is not ’can we do it?’ but ’should we do it?’," he told the BBC. "The technical part is not complex, but I don’t think that’s going to be the very great difficulty... The moral debate is obviously going to have to take place before the first facial transplantation."
    The British Association of Plastic Surgeons will discuss the microsurgical procedure, which could give new skin, bone, nose, chill, lips and ears from diseased donors to patients disfigured by accidents, burns or cancer. But surgeons could have trouble finding enough willing donors. Butler said his survey of doctors, nurses and members of the public showed most would accept a face transplant but few were willing to donate their own after dying.
    Despite a number of moral concerns, Christine Piff, who founded the charity Let’s Face It after suffering a rare facial cancer 25 years ago, welcomed the possibility of face transplants. She rejected the idea that the procedure would mean people would end up living with a dead person’s face. "There are so many people without faces, I have half a face.., but we are all so much more than just a face... you don’t take on their personality. You are still you," she told reporters. "If we can donate other organs of the body, then why not the face? I can’t see anything wrong with it."
Questions 16 to 18 are based on the passage you have just heard.
16. What makes the operation of face transplant possible?
17. What is the biggest obstacle that stays in the way of facial transplantation?
18. What is most people’s opinion of face transplant?