问题详情

What makes it so hard for the face-recognition systems to work"effectively？
A．The computers are not so advanced.
B．The faceprints of the mugshots fed in the computers are never identical with those of real persons.
C．It is very hard for the operators to learn to control the system.
D．People seldom look straight at the camera.请帮忙给出正确答案和分析，谢谢！