The correct option is D All of these
Neurotransmitters are endogenous chemicals that enable neurotransmission. It is a type of chemical messenger which transmits signals across a chemical synapse, such as a neuromuscular junction, from one neuron (nerve cell) to another "target" neuron.
Along with the neurotransmitters given above there are still more neurotransmitters like Noradrenaline, Acetylcholine, Glutamate, GABA, etc,.