**Core Concept**
The extensor retinaculum of the wrist is a fibrous band that provides support and stability to the wrist by forming four compartments. Each compartment contains specific tendons that are protected from injury and irritation by this retinaculum. The fourth compartment is of particular interest in this question.

**Why the Correct Answer is Right**
The fourth compartment of the extensor retinaculum contains the tendons of the extensor pollicis brevis, abductor pollicis longus, and extensor pollicis longus muscles. These muscles are responsible for thumb extension, abduction, and flexion, respectively. The tendons of these muscles are protected by the fourth compartment, which is a critical anatomical structure for wrist stability and function.

**Why Each Wrong Option is Incorrect**
* **Option A:** The first compartment contains the tendons of the abductor pollicis longus and extensor pollicis brevis muscles, not the fourth compartment.
* **Option B:** The second compartment contains the tendons of the extensor carpi radialis brevis and extensor carpi radialis longus muscles, not the fourth compartment.
* **Option C:** The third compartment contains the tendon of the extensor pollicis longus muscle, which is part of the fourth compartment, so this option is incorrect.

**Clinical Pearl / High-Yield Fact**
The fourth compartment of the extensor retinaculum is a common site for wrist injuries, particularly in athletes who engage in repetitive wrist movements. Awareness of this anatomical structure is essential for diagnosis and treatment of wrist injuries.

**Correct Answer: D.**