A community health nurse is performing a vision screening on a 4-month-old infant. When shining a light source into the infant's visual field, which of the following is an expected finding?

The correct answer is A. Infants at 4 months of age typically exhibit the visual reflex known as the "light reflex." When a light source is shined into their visual field, their eyes should turn towards the light. This is a normal physiological response indicating the development of visual tracking abilities. Choice B is incorrect as the head turning away from the light is not a typical response at this age. Choice C is incorrect as the eyes remaining focused toward the floor would not be expected during a vision screening. Choice D is incorrect as closing their eyes is not a typical response to a light stimulus at this age.