Myasthenia Gravis Is an Autoimmune Disorder in Which Antibodies Attack

Myasthenia gravis is an autoimmune disorder in which antibodies attack acetylcholine receptors. The resulting muscle weakness is likely due to

A) increasing the amount of acetylcholinesterase in the synapse.
B) making the cells less permeable to sodium ions.
C) increasing the amount of potassium ion in the intercellular fluid.
D) making the plasma membranes more permeable to calcium ion.
E) antibodies competing with acetylcholinesterase for acetylcholine.