**Core Concept**
The parasympathetic nervous system (PNS) plays a crucial role in regulating various autonomic functions, including salivation. The PNS stimulates the salivary glands to produce saliva, which is essential for food digestion and oral health.

**Why the Correct Answer is Right**
The PNS stimulates the salivary glands through the release of acetylcholine (ACh) at the parasympathetic nerve terminals. ACh binds to muscarinic receptors (M3 subtype) on the salivary gland cells, leading to an increase in saliva production. This is mediated by the activation of the Gq protein-coupled signaling pathway, which results in the stimulation of phospholipase C and the subsequent increase in intracellular calcium levels. The increased calcium levels trigger the release of saliva from the salivary gland cells.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the sympathetic nervous system (SNS) actually decreases saliva production by releasing norepinephrine, which binds to beta-2 adrenergic receptors on the salivary gland cells, leading to a decrease in saliva secretion.
* **Option B:** This option is incorrect because the PNS does not stimulate the salivary glands to produce mucus. The PNS does stimulate the mucous membranes in the respiratory and gastrointestinal tracts, but not the salivary glands.
* **Option D:** This option is incorrect because the PNS does not stimulate the salivary glands to produce enzymes. The PNS does stimulate the salivary glands to produce saliva, but not digestive enzymes.

**Clinical Pearl / High-Yield Fact**
The PNS is responsible for the "rest and digest" functions of the body, including salivation, digestion, and elimination. The PNS can be stimulated by the vagus nerve, which is responsible for the parasympathetic innervation of the salivary glands.

**Correct Answer:** C.