C is the most assertive refusal of all the examples, and it is also the safest. Bravo to Lindsay for not allowing people under the influence drive her around, it isn't a good idea to use subtances and operate machinery. Hope this helps!
Whether it is a real emergency or a threat to you and/or the public
Neurotransmitters would continue to bind and rebind with the postsynaptic receptors, which would continue induction of a signal in the postsynaptic neurons, which would repropagate the initial signal.
The case in drugs that block reuptake transporters (such as in serotonin reuptake inhibitor and norepinephrine reuptake inhibitor antidepressants, and dopamine reuptake inhibition found with cocaine and methylphenidate).