Which of These Techniques Is the Key Factor in a Telescope

Multiple Choice

Which of these techniques is the key factor in a telescope that uses adaptive optics to correct for atmospheric distortion of images, or "seeing"?

A) Computer-controlled motors rapidly adjust the orientation and position of the separate primary mirrors in a multiple-mirror telescope (MMT) .
B) A corrector lens compensates for image distortion by electronic control of its shape.
C) Computer-controlled motors adjust the position and shape of one of the small mirrors within the optics many times per second.
D) The light rays are focused electronically, without the use of lenses or mirrors.