What Does the Neuron Doctrine Propose About Neuronal Systems

What does the neuron doctrine propose about neuronal systems?

A) That neurons are not continuous and that they must communicate by contact
B) That neurons form continuous circuits
C) That the neuron contains three distinct parts: the cell body, the axon, and the dendrites
D) That neurons can become visible under a microscope because of histology
E) That neurons are the most important cell in the body