Final answer:
The nurse should plan interventions that aim to reduce anxiety associated with obsessive thoughts in a client experiencing symptoms of obsessive-compulsive disorder (OCD).
Step-by-step explanation:
The client is experiencing symptoms of obsessive-compulsive disorder (OCD) characterized by recurrent, distressing thoughts of contamination, causing anxiety and impacting their daily life for several hours a day. The nurse should plan interventions that focus on reducing anxiety associated with these obsessive thoughts (option D). This may involve techniques such as cognitive-behavioral therapy (CBT), exposure and response prevention (ERP), and the use of medication like selective serotonin reuptake inhibitors (SSRIs).