At a synapse, adequate stimulation causes the presynaptic cell to release which of the following?
action potentials that bind to receptors on the postsynaptic cell
neurotransmitter that bind to axons on the postsynaptic cell
action potentials that bind to axons on the postsynaptic cell
neurotransmitters that bind to receptors on the postsynaptic cell
i think this one is
d.

Neurotransmitters that bind to receptors on the postsynaptic cell

Synaptic Vesicles

The neuron, a cell that composes the nervous system. For example a brain, an organ composed of thousands of neural fibers and glial cells that performs many important organismic functions. 
Neurons are specialised cells that have dendrites, axons and terminal buttons that sends and receives stimuli from the environment and transduces it into a meaningful information and understand the complexities which the brain now functions.

Where are the options?