Why can you not see objects in a dim lit room when you come from a brightly lit room?

Correct option is B

The correct answer is (b) The iris contracts the pupil to allow less light to enter the eye.
 When you move from a brightly lit room to a dimly lit room, your eyes take some time to adjust due to the change in light intensity. In bright light, the iris contracts the pupil to reduce the amount of light entering the eye to protect the retina from excessive light exposure. This contraction limits the light entering the eye.
Information Booster:
 Pupil Adjustment: When you move to a dimly lit room, the pupil needs to dilate (enlarge) to allow more light to enter the eye. This dilation process takes a few moments, during which you may not see objects clearly.
 Iris Function: The iris, which controls the size of the pupil, contracts in bright light and dilates in low light to regulate the amount of light entering the eye.
 Adaptation Time: This adjustment process, known as dark adaptation, involves both the mechanical adjustment of the pupil and chemical changes in the photoreceptor cells in the retina.