Which among the following controls the amount of light entering the eye?

The pupil is a hole in the iris into which light from the surroundings enters our eye. When the surroundings emit a lot of light it contracts to limit the amount of light that reaches our eyes. When it is too dark, the pupil becomes larger to let in a large amount of light to get a better vision in the dark. Therefore, the pupil controls how much light enters the eye.