Final answer:
John experiencing the color red in his vision upon hearing a baby cry is an example of synesthesia, where one sensory experience involuntarily triggers a perception in another sensory modality.
Step-by-step explanation:
The phenomenon of synesthesia involves the mixing of sensory or cognitive pathways, such that the stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway. From the provided options, John, upon hearing the baby cry, starts to see the color red in the extremities of his visual field, best describes someone who is experiencing the phenomenon of synesthesia. This is because synesthesia is characterized by the association of one sense with experiences typically related to another sense. In John's case, the auditory input (hearing the baby cry) is leading to a visual experience (seeing the color red), which is a classic example of synesthetic perception