Answer:
The best answer to fill in the blank here would be an anxiety disorder, best known as obsessive compulsive disorder.
Step-by-step explanation:
Anxiety disorders, especially as acute and serious as obsessive compulsive disorder, can cause a person to lose any hopes of sleeping well. In turn the lack of sleep will also increase anxiety and can cause the appearance of compulsive actions, like the ones Angela is displaying. Due to anxiety, Angela cannot rest until she has taken several trips to check on all the locks. This action is typical of the obsessive compulsive disorder, and they display that Angela has a severe case of anxiety that triggers her obsession with the locks, and motivates the compulsive action of going back and forth to check, to the detriment of her resting and sleeping hours. All of this is characteristic of OCD.