Three presynaptic neurons A B and C generate excitatory pote
     Three presynaptic neurons (A, B, and C) generate excitatory potentials on a single post-synaptic neuron (X). Neurons A, B, and c each cause a 5mV depolarization at the axon hillock. Based on this information, which of the following is true?  Neurons A, B, and C release neurotransmitters that open ligand-gated Na^+ channels on Neuron X.  Neurons A, B, and C activate voltage-gated Na^+ channels on the soma or dendrites of Neuron X.  Because neurons A, B, and C all generate a 5mv depolarization at the axon hillock, they must all generate the same-sized graded potential at their individual synapses.  Neurons A, B, and C generate action potentials on Neuron X. 
  
  Solution
The correct option is..................Neurons A,B, C generate action potential on neuron X.

