The photoreceptors of the retina

a. convert chemical signals into electrical signals
b. convert sound waves into electrochemical signals
c. convert light energy into electrochemical signals
d. convert light energy into electromagnetic signals

Option c

Explanation:

The photoreceptors are found in the eyes of the human body. These receptors absorbs light from the surrounding and converts it into electrochemical signal.

The signals from eyes are are transferred to the brain so that we can see the objects and recognize it.The signals are transferred through the neurotransmitter.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

bradykinin is a physiologically and pharmacologically active peptide of the kinin group of proteins, consisting of nine amino acids.