Choose the INCORRECT statement

a. The motor end plate membrane is only capable of generating graded potentials, but it is contiguous with the skeletal muscle sarcolemma, which can generate action potentials.
b. Propagation of an action potential through the T-tubules into the sarcoplasmic reticulum triggers the release of Ca++ into the cytoplasm of a skeletal muscle fiber.
c. The generation of suprathreshold endplate potentials in multiple muscle fibers could be due to the increased frequency of action potential generation at the axon hillock of a single motor neuron.
d. A greater amount of ACh would be found in the presynaptic vesicles of a motor unit that fired several action potentials after exposure to Botulinum toxin, than in a motor unit that fired several action potentials after exposure to the venom of the Krait snake (which contains ?-bungarotoxin).

it applies all or none law. either it generates full threshold level potential or it does not produce any potential. after being released from the presynaptic neuron, ACh binds with the receptor of the postsynaptic neuron, which leads to the depolarization of the cell membrane by the increased transportation of Na and K. then, MEPP leads to increased depolarization in the postsynaptic membrane which is also known as end-plate potential.

A. is the incorrect statement.