Which part of a reflex arc would connect a sensory neuron from the face and neck to a motor neuron in a lower section of the spinal cord?

The correct answer is interneuron.

Explanation:

In a reflex arch, a receptor determines a stimulus, like the receptors present in the tip of a finger. As an outcome, the impulses produced because of the stimulus are conducted via the sensory neurons to the interneuron or the relay neurons found in the spinal cord.  

The relay neurons associate sensory neurons to the motor neurons. The motor neurons mediate impulses towards the effector. The effector generates response like moving away from a stimulus.