**Core Concept**
Fisch classification is a system used to categorize the extent of nasopharyngeal angiofibroma, a rare, benign tumor that arises from the sphenopalatine foramen. This classification helps in determining the surgical approach and predicting the potential for recurrence.

**Why the Correct Answer is Right**
The Fisch classification is based on the tumor's extent and its relation to surrounding structures, such as the nasal cavity, sinuses, and cranial nerves. It takes into account the tumor's size, location, and potential for invasion into critical areas. The classification is essential for surgeons to plan the appropriate surgical approach and to predict the likelihood of recurrence.

**Why Each Wrong Option is Incorrect**
* **Option A:** Fisch classification is not used for thyroid tumors. Thyroid tumors are typically classified using the Brachythyroid classification or the TNM system.
* **Option B:** The TNM system is used for staging various types of cancer, including nasopharyngeal cancer, but it is not specific to nasopharyngeal angiofibroma.
* **Option C:** The Andrews classification is used for evaluating the extent of maxillary sinus tumors, but it is not applicable to nasopharyngeal angiofibromas.

**Clinical Pearl / High-Yield Fact**
Fisch classification is essential for surgeons to accurately plan the surgical approach and predict the potential for recurrence in patients with nasopharyngeal angiofibroma. It helps in minimizing the risk of complications and improving patient outcomes.

**Correct Answer: C.**