Consider a system that contains three neurons in a culture dish bathed in normal physiological saline. All three neurons are healthy. Neuron A synapses onto Neuron B. Neuron B synapses onto Neuron C. Neuron A has glycine in its synaptic vesicles. Neuron B has ACh (acetylcholine) in its synaptic vesicles. The only ligand-gated receptors in Neuron A are AMPA receptors. The only ligand-gated receptors in the plasma membrane of Neuron B are glycine receptors. The only ligand-gated receptors in the plasma membrane of Neuron C are mACh (muscarinic ACh) receptors. All 3 neurons have no other ligand-gated receptors in their plasma membranes. All 3 neurons have a sodium equilibrium potential of +60 millivolts. All 3 neurons have a potassium equilibrium potential of -86 millivolts. Neuron A and Neuron B have a chloride equilibrium potential of -80 millivolts. Neuron C has a chloride equilibrium potential of -20 millivolts. The threshold for an action potential in all 3 neurons is -55 millivolts. At 1:55 AM, glutamate is added to the physiological saline. At 2:00 AM, the action potential firing rate of each neuron is 100 Hz. Which of the following will lead to a decrease in Neuron C's action potential firing rate?

A. At 2:01 AM, ACh is added to the bath.

B. At 2:01 AM, strychnine is added to the bath.

C. At 2:01 AM, CNQX is added to the bath.

D. A and B.

E. A and C.

F. B and C.

G. A, B, and C.

H. None of the above.