## **Core Concept**
The question tests knowledge of sialolithiasis, which refers to the formation of stones within the salivary glands. This condition most commonly affects the **submandibular gland** due to its anatomy and the characteristics of its secretions.

## **Why the Correct Answer is Right**
The **submandibular gland** is the commonest site for salivary gland stones, accounting for about 80-90% of all sialoliths. This is because the submandibular gland produces more **calcium-rich secretions** compared to other salivary glands, and its duct (Wharton's duct) has an upward course against gravity, which facilitates the deposition of minerals and the formation of stones.

## **Why Each Wrong Option is Incorrect**
* **Option A:** The **parotid gland** is less commonly affected by stones, partly because its secretions are more serous and less likely to form stones.
* **Option C:** The **sublingual gland** produces mucinous secretions and is rarely affected by stones, likely due to the composition of its secretions and its ductal anatomy.
* **Option D:** The **minor salivary glands** are not typically associated with stone formation, possibly due to their small size and the nature of their secretions.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that sialolithiasis often presents with **obstructive symptoms** such as pain and swelling of the affected gland, especially during meals. The presence of a stone in the duct can be confirmed by **palpation** or imaging studies like sialography or ultrasound.

## **Correct Answer:** B. Submandibular gland.