Q. When a person walking in bright sunlight enters a dark room, he is not able to see clearly for a little while because

• (A) The iris is unable to dilate the pupil immediately SOUND
• (B) The iris is unable to contract the pupil immediately
• (C) The eye muscles cannot immediately change the focal length of the eye lens
• (D) The retina retains the bright images for some time and becomes momentarily insensitive