## Core Concept
Mikulicz's disease is a rare, idiopathic condition characterized by the enlargement of salivary and lacrimal glands due to an autoimmune process. It is often associated with **IgG4-related disease**, a systemic fibroinflammatory condition. The disease presents with painless swelling of the glands.

## Why the Correct Answer is Right
The correct answer, **Mikulicz's disease**, is right because it specifically refers to an autoimmune condition that affects the salivary and lacrimal glands, leading to their enlargement. This condition is now considered part of the spectrum of **IgG4-related disease**, which is characterized by tumor-like swelling of involved organs, dense lymphoplasmacytic infiltration, and often, elevated serum IgG4 levels.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because it does not accurately describe Mikulicz's disease. Without the specific text of option A, we can infer that any option not describing an autoimmune condition related to salivary and lacrimal gland enlargement would be incorrect.
- **Option B:** Similarly, this option is incorrect if it does not align with the definition and characteristics of Mikulicz's disease as an autoimmune condition affecting the salivary and lacrimal glands.
- **Option D:** This option is incorrect if it describes a different condition or does not accurately represent Mikulicz's disease.

## Clinical Pearl / High-Yield Fact
A key point to remember is that Mikulicz's disease is often associated with **IgG4-related disease**, and its management may involve corticosteroids and sometimes other immunosuppressive drugs. Clinicians should also be aware of the potential for other systemic involvement in IgG4-related disease.

## Correct Answer Line
**Correct Answer: C. Mikulicz's disease.**