The Enteric Nervous System Is Still Not Well Understood Because

The enteric nervous system is still not well understood because

A) scientists have only recently begun to study its function.
B) the human enteric nervous system does not resemble that of any other species.
C) it contains an extremely large number of densely interconnected neural circuits.
D) electrical recordings cannot be used on these neurons.
E) it uses a different set of neurotransmitters than those found elsewhere.