**Core Concept**
Acoustic nerve tumors, also known as vestibular schwannomas, are benign tumors that arise from the Schwann cells of the vestibulocochlear nerve (cranial nerve VIII). The earliest symptoms of acoustic nerve tumors are related to the compression of the nerve and its surrounding structures.

**Why the Correct Answer is Right**
The correct answer is related to the compression of the vestibulocochlear nerve, which affects the balance and hearing functions. The earliest symptom of acoustic nerve tumor is **subjective hearing loss**. This occurs due to the compression of the cochlear division of the vestibulocochlear nerve, which carries sound information from the ear to the brain. The compression leads to a decrease in the transmission of sound signals, resulting in hearing loss.

**Why Each Wrong Option is Incorrect**
**Option A:** Tinnitus, or ringing in the ears, is a common symptom of acoustic nerve tumors, but it is not the earliest symptom. Tinnitus develops as the tumor grows and compresses the nerve further.
**Option B:** Balance problems, such as vertigo or dizziness, are also associated with acoustic nerve tumors, but they are not the earliest symptom. Balance problems occur as the tumor affects the vestibular division of the vestibulocochlear nerve.
**Option C:** Facial weakness or numbness is not a typical symptom of acoustic nerve tumors.

**Clinical Pearl / High-Yield Fact**
Remember that the earliest symptom of acoustic nerve tumors is often subtle, and patients may not seek medical attention until the symptoms worsen. A high index of suspicion is necessary for early diagnosis.

**Correct Answer: C. Facial weakness or numbness is not a typical symptom of acoustic nerve tumors.**