what is the difference between excitatory and inhibitory neurotransmitters? a. excitatory neurotransmitters make an action potential less likely to occur while inhibitory neurotransmitters make an action potential more likely to occur b. excitatory neurotransmitters make an action potential more likely to occur while inhibitory neurotransmitters make an action potential less likely to occur c. excitatory and inhibitory neurotransmitters both decrease the chances of an action potential d. excitatory and inhibitory neurotransmitters both increase the chances of an action potential