Concept: A hypnotic is a medicine that helps a person fall asleep. Many older sleep medicines belong to the benzodiazepine family. But there is a newer group called the non-benzodiazepine hypnotics, often called the "Z-drugs" because their names start with Z.
Step 1: Look at each name. Diazepam, Lorazepam and Alprazolam all end in "-azepam" or "-azolam", which tells us they are benzodiazepines.
Step 2: Zolpidem does not have that benzodiazepine ending. It is one of the famous Z-drugs and is used to treat trouble sleeping. So it is the non-benzodiazepine hypnotic here.