Which of the Following Is TRUE of Ligand-Gated Ion Channels

Which of the following is TRUE of ligand-gated ion channels?

A) They bind ions with high affinity.
B) They tend to allow any ion to pass through the channel.
C) The intracellular domain of the channel contains the binding site for the ligand.
D) They open upon binding the ligand to allow specific ions to pass through them.
E) Ligand binding closes the channels preventing further ion passage through the channel.