Cyclic Guanosine Monophosphate (CGMP) Found in the Cytoplasm of Photoreceptors

Multiple Choice

Cyclic guanosine monophosphate (cGMP) found in the cytoplasm of photoreceptors is usually found in

A) high quantities in the dark, where its presence keeps ion channels open.
B) low quantities in the dark, during which ion channels are closed.
C) high quantities after the absorption of photons, which causes ion channels to open.
D) low quantities after the absorption of photons, which causes ion channels to open.
E) high quantities after the absorption of photons, which causes ion channels to close.