A particular neuron (A) is post-synaptic to two other neurons (B and C). One of the pre-synaptic neurons (B) formed a synapse on cell A's axon initial segment. Neuron C formed a synapse on one of A's dendrites. Both B and C produce EPSPs (excitatory postsynaptic potentials) of the same magnitude in neuron A but one of these two pre-synaptic cells affects action potential generation by neuron A much more than the other. Which neuron, B or C, has the greater effect on neuron A? Explain how this effect is generated in neuron A and why one neuron has a greater effect than the other.