The correct answer is option (a) "Increase the amount of neurotransmitters secreted".
Explanation:
Presynaptic neurons are helpful cells at chemical synapsis because they increase the intensity of the transmitted signals by increasing the amount of neurotransmitters secreted. The neurotransmitters are the carriers of information from the pre-synaptic—sending—neuron to the post-synaptic—receiving—cell, which results in an action potential.
