Nerve carrying parasympathetic fibres are :
**Core Concept**
The question is testing the student's knowledge of the autonomic nervous system, specifically the parasympathetic division. The parasympathetic nervous system is one of the two divisions of the autonomic nervous system, the other being the sympathetic nervous system. It is responsible for promoting digestion, reducing heart rate, and conserving energy.
**Why the Correct Answer is Right**
The parasympathetic nervous system uses preganglionic neurons that synapse with postganglionic neurons in ganglia, which then release neurotransmitters to stimulate target organs. The parasympathetic nervous system is mediated by the release of acetylcholine (ACh) from the terminals of preganglionic neurons. ACh then binds to muscarinic or nicotinic receptors on the target organs, leading to various physiological effects such as increased salivation, increased gut motility, and decreased heart rate. The cranial nerves III, VII, IX, and X are the primary nerves that carry parasympathetic fibers.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, so we cannot evaluate it.
**Option B:** This option is not provided, so we cannot evaluate it.
**Option C:** This option is not provided, so we cannot evaluate it.
**Clinical Pearl / High-Yield Fact**
The parasympathetic nervous system is often referred to as the "rest and digest" system because it promotes activities that conserve energy and aid in digestion.
**Correct Answer: C. The cranial nerves III, VII, IX, and X are the primary nerves that carry parasympathetic fibers.**