**Core Concept**
The barbed broach is a dental instrument used in root canal therapy to remove infected or damaged pulp tissue from the root canal of a tooth. This instrument plays a crucial role in the extirpation process, which is essential for preventing further infection and promoting healing.

**Why the Correct Answer is Right**
The barbed broach works by using its barbed ends to grasp and remove pulp tissue from the root canal. As the instrument is withdrawn from the canal, the barbs pull out the infected tissue, helping to ensure that the canal is completely cleaned and disinfected. This is a critical step in root canal therapy, as it helps to prevent the spread of infection and promotes the healing of the surrounding tissues. The barbed broach is specifically designed for this purpose, making it an essential tool in the dentist's arsenal.

**Why Each Wrong Option is Incorrect**
**Option B:** Enlargement of canal - While the barbed broach may be used in conjunction with other instruments to enlarge the root canal, its primary function is not enlargement. Instruments like reamers and files are more commonly used for this purpose.
**Option C:** Obturation of canals - Obturation refers to the process of filling a root canal with a material, such as gutta-percha, to seal it off from the surrounding tissues. The barbed broach is not used for obturation, but rather for the removal of pulp tissue.

**Clinical Pearl / High-Yield Fact**
The barbed broach is a classic example of a dental instrument that is specifically designed for a particular task. Remembering the correct function of this instrument can help you to avoid common mistakes in root canal therapy, such as using the wrong instrument for a particular step in the procedure.

**Correct Answer:**
✓ Correct Answer: A. Extirpation of pulp