**Core Concept**
The pelvic pain is mediated by the autonomic nervous system, specifically through the sympathetic and parasympathetic branches. This system is responsible for regulating involuntary functions, including pain perception in the pelvic region. The autonomic nervous system plays a crucial role in modulating pain transmission and is closely linked to the hypothalamic-pituitary-adrenal axis.

**Why the Correct Answer is Right**
The autonomic nervous system, comprising the sympathetic and parasympathetic branches, mediates pelvic pain through the release of neurotransmitters such as substance P and calcitonin gene-related peptide (CGRP) from the dorsal root ganglia. These neurotransmitters are involved in the transmission of pain signals from the pelvic region to the spinal cord and brain. The autonomic nervous system also modulates the release of hormones such as prostaglandins, which contribute to pain perception. The sympathetic branch, in particular, is involved in the transmission of pain signals from the pelvic region, including the uterus, bladder, and rectum.

**Why Each Wrong Option is Incorrect**
**Option A:** The pudendal nerve is primarily responsible for transmitting sensory information from the genitalia and perineum, but it is not the primary mediator of pelvic pain.

**Option B:** The sciatic nerve is a major nerve that runs from the lower back down to the legs, but it does not directly mediate pelvic pain.

**Option D:** While the other options are incorrect, none of the above is not the correct answer, as the autonomic nervous system is indeed responsible for mediating pelvic pain.

**Clinical Pearl / High-Yield Fact**
The autonomic nervous system plays a crucial role in modulating pain perception in the pelvic region, and its dysregulation can contribute to chronic pelvic pain syndromes. Understanding the role of the autonomic nervous system in pain transmission is essential for effective management of pelvic pain.

**✓ Correct Answer: C. Autonomic nerves**