**Core Concept**
The ANB angle is a cephalometric measurement used in orthodontics and maxillofacial surgery to assess the relationship between the maxilla and mandible. It is an important parameter in evaluating facial aesthetics and planning orthodontic treatment.

**Why the Correct Answer is Right**
The ANB angle is calculated by drawing a line from the point A (the most anterior point on the maxilla) to the point N (the most posterior point on the maxilla) and another line from the point B (the most anterior point on the mandible) to the point N. The angle formed by these two lines is the ANB angle. This measurement is used to determine the anteroposterior relationship between the maxilla and mandible, with a normal ANB angle ranging from 2-4 degrees. A positive ANB angle indicates a Class II skeletal relationship, while a negative ANB angle indicates a Class III skeletal relationship.

**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because the ANB angle is not related to the measurement of facial height.
* **Option B:** Incorrect because the ANB angle is not a measure of facial width.
* **Option C:** Incorrect because the ANB angle is not a measure of occlusal plane inclination.

**Clinical Pearl / High-Yield Fact**
A normal ANB angle is essential for maintaining facial aesthetics and proper dental occlusion. A significant deviation from the normal range can lead to orthodontic treatment to correct the skeletal relationship between the maxilla and mandible.

**Correct Answer: D.**