**Core Concept**
Mikulicz's disease is a rare autoimmune disorder characterized by bilateral swelling of the salivary and lacrimal glands, leading to symptoms such as dry mouth and eyes. This condition is caused by an autoimmune response against the glandular tissues, resulting in inflammation and enlargement of the affected glands.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of Mikulicz's disease, which involves an autoimmune response against the glandular tissues. The disease is often associated with other autoimmune conditions, such as Hashimoto's thyroiditis, Sjögren's syndrome, and rheumatoid arthritis. The inflammation and enlargement of the glands lead to symptoms such as dry mouth (xerostomia) and dry eyes (xerophthalmia).

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because Mikulicz's disease is not primarily a parotid gland disorder, although the parotid glands can be affected.
* **Option B:** This option is incorrect because Sjögren's syndrome is a separate autoimmune disorder that primarily affects the exocrine glands, particularly the salivary and lacrimal glands.
* **Option C:** This option is incorrect because Hashimoto's thyroiditis is an autoimmune disorder that affects the thyroid gland, whereas Mikulicz's disease affects the salivary and lacrimal glands.

**Clinical Pearl / High-Yield Fact**
Mikulicz's disease often presents with a triad of symptoms: dry mouth, dry eyes, and swelling of the salivary and lacrimal glands. A high index of suspicion is necessary for early diagnosis, as the symptoms can be nonspecific and may resemble other conditions.

**Correct Answer:** B. Sjögren's syndrome