## **Core Concept**
The question describes a patient presenting with symptoms of anxiety, including tension, sympathetic and parasympathetic symptoms, and insomnia. This clinical presentation suggests a diagnosis related to anxiety disorders.

## **Why the Correct Answer is Right**
The symptoms described, such as being a "nervous person," feeling tense all the time, exhibiting both sympathetic (e.g., tachycardia, sweating) and parasympathetic symptoms (e.g., nausea, abdominal discomfort), and having insomnia, are characteristic of **Generalized Anxiety Disorder (GAD)**. GAD is a condition where an individual experiences excessive worry about everyday things for at least six months, which is difficult to control. This worry is associated with symptoms such as restlessness, being easily fatigued, difficulty concentrating, irritability, muscle tension, and sleep disturbance.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but typically, anxiety disorders include specific phobias, social anxiety disorder, panic disorder, and GAD. Without the specific option, we can't directly address its incorrectness but can infer that it likely doesn't match the broad, chronic nature of GAD.
- **Option B:** Similarly, this option is not provided. However, other anxiety disorders like panic disorder (characterized by panic attacks) or specific phobias (characterized by fear of a specific object or situation) might not fit as well with the chronic, pervasive symptoms described.
- **Option C:** Without the specific details of this option, we can speculate it might refer to another psychiatric or medical condition not primarily characterized by the symptoms of anxiety and tension described.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl for anxiety disorders, particularly GAD, is the use of the **GAD-7 questionnaire** as a screening tool. It assesses the severity of generalized anxiety disorder and can help in diagnosing GAD. Additionally, first-line treatments often include selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), as well as cognitive-behavioral therapy (CBT).

## **Correct Answer:** D. Generalized Anxiety Disorder.