The author's attitude towards applied bionics is ______.

A．video signals can be transformed into light patterns
B．bionic machines have existed for centuries
C．artificial devices such as arms, legs and eyes require better control than bionic machines
D．science has made great advances in electronics

A．first developed applied bionics
B．was the first to operate on the heart of a patient
C．developed the artificial heart
D．used more sophisticated methods to do "open heart" surgery