**Core Concept**
The three cornered flap is a surgical technique used in the removal of impacted third molars, involving the creation of a flap to access the impacted tooth. The **lingual nerve** and **inferior alveolar nerve** are at risk during this procedure due to their anatomical location.

**Why the Correct Answer is Right**
The correct answer is related to the anatomical structures at risk during the procedure. The **lingual nerve** is particularly vulnerable during the release of the incision in a three cornered flap, as it runs close to the site of the incision.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it is not directly related to the common nerves at risk in this procedure.
**Option B:** This is not the primary structure at risk in this specific context.
**Option D:** This option is also incorrect as the primary concern is not this structure during the release of the incision.

**Clinical Pearl / High-Yield Fact**
It is crucial to identify and preserve the **lingual nerve** during surgical removal of third molars to avoid complications such as numbness or altered sensation of the tongue.

**Correct Answer:** D. Lingual nerve