The simplest version of a withdrawal reflex involves a

A) pain receptor synapsing onto a motor neuron in the spinal cord.
B) pain receptor that projects to the thalamus, which then projects to motor cortex and then down to the spinal cord.
C) motor neuron within the spinal cord that is spontaneously active.
D) sensory neuron in visual cortex that synapses onto a motor neuron in the spinal cord.
E) muscle fiber connecting onto an interneuron.
c

Answer: A
Rationale: The simplest version of a withdrawal reflex involves a pain receptor synapsing onto a motor neuron in the spinal cord.