**Core Concept**
Parotid gland fatty change is a histopathological finding associated with various conditions, primarily reflecting an alteration in the gland's normal cellular composition and function. This change is often seen in the context of chronic inflammation, autoimmune disorders, or as a result of salivary gland dysfunction.

**Why the Correct Answer is Right**
The correct answer is related to Sjögren's syndrome, an autoimmune disorder characterized by inflammation and destruction of the salivary and lacrimal glands. The parotid gland fatty change is a hallmark feature of this condition, resulting from the replacement of normal glandular tissue with fatty infiltrates. This process is mediated by chronic inflammation and the subsequent release of various cytokines and chemokines, which disrupt the normal glandular architecture.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while malnutrition can cause changes in the parotid gland, it is not the primary cause of fatty change. Malnutrition may lead to atrophy of the gland, but it does not specifically result in fatty infiltration.
**Option B:** This option is incorrect because chronic pancreatitis is not directly associated with parotid gland fatty change. While pancreatitis can lead to changes in the pancreas, it does not specifically affect the parotid gland.
**Option C:** This option is incorrect because mumps virus infection can cause inflammation of the parotid gland, but it is not typically associated with fatty change. Mumps parotitis is a self-limiting condition that resolves with treatment.

**Clinical Pearl / High-Yield Fact**
The presence of parotid gland fatty change should raise suspicion for Sjögren's syndrome, an autoimmune disorder that requires prompt evaluation and management to prevent long-term sequelae.

**Correct Answer:** C.