Final answer:
The action that most clearly illustrates obsessive-compulsive disorder is frequent handwashing due to a fear of germs, aligning with the characteristic compulsions and obsessions seen in OCD.
Step-by-step explanation:
The behavior most clearly illustrating obsessive-compulsive disorder (OCD) among the options provided is b) Frequent handwashing due to a fear of germs. This type of behavior is typically driven by obsessions, which are persistent, unwanted thoughts causing distress or anxiety. Individuals with OCD often engage in compulsions or rituals—in this case, excessive handwashing—to alleviate the distress caused by these obsessions. OCD is characterized by a range of symptoms including impaired social skills, repetitive motor behaviors, strict adherence to certain rituals, and preoccupation with specific subjects.
Common obsessions involve concerns over cleanliness and contamination, which compel sufferers to perform cleansing rituals repeatedly. This aligns with the frequent handwashing scenario. It's important to distinguish OCD from normal worries about real problems; OCD symptoms are excessive and not a rational response to an actual threat. The underlying neural mechanisms involve abnormal brain-behavior relationships, contributing to the reinforcement of compulsive actions and obsessive thoughts.