## **Core Concept**
The facial nerve, also known as cranial nerve VII, is primarily responsible for controlling the muscles of facial expression. However, there is an exception to this general rule, which involves understanding the innervation of specific muscles in the face.

## **Why the Correct Answer is Right**
The muscles of facial expression are indeed innervated by the facial nerve (cranial nerve VII). However, the muscle responsible for the exception is the **muscle of mastication**, specifically the **masseter muscle**, **temporalis muscle**, **medial pterygoid muscle**, and **lateral pterygoid muscle**, which are supplied by the **trigeminal nerve (cranial nerve V)**, specifically the **mandibular division (V3)**. Among the given options, if one specifically refers to a muscle not supplied by the facial nerve but is commonly known, it would relate to the muscles of mastication.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option would be incorrect if it referred to a muscle supplied by the facial nerve, as the question asks for an exception.
- **Option B:** Similarly, if this option also referred to a muscle supplied by the facial nerve, it would be incorrect for the same reason.
- **Option D:** This would also be incorrect if it represented another muscle innervated by the facial nerve.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the **frontalis muscle**, which is involved in eyebrow elevation, is innervated by the facial nerve but the **corrugator supercilii** and **procerus** muscles are also innervated by the facial nerve. However, a clinically relevant exception concerning a larger group of muscles is that the **muscles of mastication** (masseter, temporalis, medial pterygoid, and lateral pterygoid) are supplied by the **trigeminal nerve**, not the facial nerve.

## **Correct Answer:** . **C. Masseter**