Answer: Increase of postsynaptic resting potential.
Explanation:
When the botulinum toxin enters the organism, it generates that there is no depolarization of the presynaptic membrane, therefore acetylcholine does not release the space between the membranes, and said neurotransmitter never reaches the receptor for the postsynaptic membrane. That is why the disease is characterized by immobility or muscular paralysis, since the action potential is never carried out on the postsynaptic membrane thanks to said toxin generated by the botulism bacteria.