**Core Concept**
Hanging is a form of asphyxial death, typically caused by the compression of the neck structures. The specific mechanism of injury can lead to various forensic and clinical manifestations.

**Why the Correct Answer is Right**
The most specific feature of hanging is the presence of a ligature mark on the neck, which is a result of the compression of the skin and underlying tissues by the noose or ligature. This mark is typically found at the level of the cricoid cartilage and the thyroid cartilage, where the force of the ligature is most concentrated. The compression of the neck structures, including the trachea, esophagus, and blood vessels, can lead to asphyxiation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while bruising may be present around the neck, it is not a specific feature of hanging. Bruising can occur in various types of trauma, including strangulation.
**Option B:** This option is incorrect because while a broken neck may occur in some cases of hanging, it is not a specific feature of this type of injury. A broken neck can occur in various types of trauma, including falls and motor vehicle accidents.
**Option C:** This option is incorrect because while a ligature mark may be present on the wrist or arm in cases of hanging, it is not a specific feature of this type of injury. A ligature mark can occur in various types of trauma, including strangulation and restraint.

**Clinical Pearl / High-Yield Fact**
In cases of suspected hanging, it is essential to examine the ligature mark carefully, as it can provide valuable information about the mechanism of injury and the angle of suspension.

**Correct Answer: C. Ligature mark on the neck.**