**Question:** True about nerve fiber C is

A. Slow conducting nerve fibers
B. Responsible for pain sensation
C. Unmyelinated
D. Conducts slowly

**Correct Answer:** C. Unmyelinated

**Core Concept:**
Nerve fibers can be classified into three categories based on their diameter, conduction velocity, and function. These are:
1. Fast conducting (A) fibers, which are myelinated and responsible for reflex actions and quick sensory responses.
2. Moderate conducting (B) fibers, like Aβ fibers, which are also myelinated and carry pain, temperature, and pressure sensations.
3. Slow conducting (C) fibers, such as Aδ and C fibers, which are unmyelinated and responsible for pain, temperature, and touch sensations.

**Why the Correct Answer is Right:**
Nerve fiber C is a type of unmyelinated nerve fiber, which means it has a lower conduction velocity compared to other types of fibers. This makes it responsible for transmitting slower signals related to pain, temperature, and touch sensations.

**Why Each Wrong Option is Incorrect:**
A. Aδ fibers, not C fibers, are responsible for slow conduction and pain sensation.
B. Aβ fibers, not C fibers, are responsible for pain sensation.
D. All fibers A, B, and C are myelinated, but C fibers are unmyelinated.

**Clinical Pearl:**
Understanding the classification of nerve fibers is crucial in clinical practice, as it helps in diagnosing various neurological disorders and interpreting patient symptoms. For example, in neuropathy, the slow conduction velocity and damage to unmyelinated fibers can lead to symptoms like numbness, tingling, and loss of pain sensation, which can be observed in conditions like diabetic neuropathy.