Assuming that action potential threshold is at -40 mV, which of these synapses are excitatory and which are inhibitory?
A) Excitatory: -30 mV; Inhibitory: -50 mV
B) Excitatory: -50 mV; Inhibitory: -30 mV
C) Excitatory: -20 mV; Inhibitory: -60 mV
D) Excitatory: -60 mV; Inhibitory: -20 mV