The answer is (D): Retinal photoreceptors.
Explanation for each option:
(A) Acetylcholine: Cones - This is incorrect. Acetylcholine is not the neurotransmitter released by cones in the dark. Cones primarily release glutamate, not acetylcholine.
(B) Glucamate: Roos - This option seems to contain a typographical error. It likely meant to refer to "Glutamate: Rods." However, glutamate is indeed the neurotransmitter released by rods in the dark, but the option as written is incorrect due to the misspelling.
(C) Cyclic GMP: B poiarcels - This is incorrect. Cyclic GMP is not a neurotransmitter; it is a secondary messenger involved in the phototransduction pathway within photoreceptor cells. The term "B poiarcels" seems to be a typographical error and does not correspond to any known biological term.
(D) Retinal photoreceptors - This is the correct answer. In the dark, retinal photoreceptors (rods and cones) release the neurotransmitter glutamate. This release is inhibited when the photoreceptors are exposed to light.
Summary: The correct answer is (D) Retinal photoreceptors, as they release glutamate in the dark.