Final answer:
The isomerization of cis-retinal in the retina initiates a neural signal, which is part of the visual transduction process.
Step-by-step explanation:
When light strikes the retina and cis-retinal undergoes isomerization, it initiates a neural signal. This process entails the conversion of light to a neural signal through the photoisomerization of retinal within the photoreceptor cells. The isomerization alters retinal's structure from a bent (cis) form to its linear (trans) form, thereby activating rhodopsin. This starts a cascade of events, leading to changes in the membrane potential of the photoreceptor cell and eventually resulting in hyperpolarization and the generation of neural signals to the brain. The correct answer to the student's question is: C) It initiates a neural signal.