**Core Concept:**
Nerve supply to the external ear is essential for understanding the anatomy and physiology of the ear. The external ear includes the pinna (auricle) and the auditory meatus. The primary nerves responsible for sensory and motor functions of the external ear are the auricular branch of the mandibular nerve (V3), the cervical sympathetic chain, and the tympanic branch of the facial nerve (VII).

**Why the Correct Answer is Right:**
The correct answer "A" refers to the tympanic branch of the facial nerve (VII), which is indeed responsible for motor functions in the external ear, specifically the muscles involved in pinna elevation, depression, and rotation. The correct answer "C" is incorrect because the external ear also receives sensory innervation from the tympanic branch of the facial nerve (VII), which is crucial for auditory functions.

**Why Each Wrong Option is Incorrect:**
Option "B" is incorrect because the cervical sympathetic chain (C1-C8) is responsible for regulating the vascular and secretory functions of the external ear, not innervating it directly. Option "D" is incorrect because the auricular branch of the mandibular nerve (V3) plays a role in sensory innervation of the pinna and auditory meatus, as well as in motor innervation for pinna elevation and depression.

**Clinical Pearl:**
The external ear is a complex structure, receiving sensory and motor innervation from different nerves. This understanding is crucial for clinical scenarios like assessing a patient's facial nerve function, interpreting neurological deficits, or diagnosing conditions affecting the ear (e.g., facial palsy).

**Correct Answer:**
.