Which of the Following Statements Regarding the Motor End Plate

Which of the following statements regarding the motor end plate of a skeletal-muscle fiber is true?

A) Muscarinic receptors in the end plate are activated by binding to acetylcholine
B) Temporal summation of end plate potentials is required in order to trigger an action potential in the muscle-fiber membrane
C) Acetylcholinesterase in the end plate membrane catalyzes the breakdown of acetylcholine
D) Sympathetic nerve fibers innervate skeletal muscle
E) All of the choices are true