单选题 The control of artificial devices is improving because ______.

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

【正确答案】 D

【答案解析】解析：由第五段第一句可知答案。