Question

structure in the hindbrain involved in regulating states of wakefulness and sleep
alfonso
poitiers
arles
pons
reims

Explanation:

The pons in the hind - brain is involved in regulating sleep - wake cycles. The other options are names (Alfonso is a name, Poitiers, Arles, and Reims are cities) and not relevant brain structures for this function.

Answer:

pons