If the Concentration of Extracellular Calcium Is Reduced at the Frog

If the concentration of extracellular calcium is reduced at the frog neuromuscular synapse, what happens to transmitter release.

A) mEPPs no longer are observed.
B) Transmitter release increases in magnitude.
C) Transmitter release does not change.
D) The quantal size remains the same, but the quantum content is reduced.
E) The quantum content remains the same, but the quantal size is reduced.