## **Core Concept**
The question tests knowledge of sialolithiasis, which is the formation of stones (calculi) within the salivary glands or their ducts. This condition most commonly affects the submandibular gland.

## **Why the Correct Answer is Right**
The submandibular gland is the commonest site for salivary gland stones due to several factors:
- **Anatomy**: The submandibular gland has a longer and more tortuous duct (Wharton's duct) that ascends against gravity to empty near the base of the tongue. This anatomy predisposes to stasis of saliva and increases the likelihood of stone formation.
- **Saliva Composition**: The submandibular gland produces a higher proportion of calcium-rich saliva compared to other salivary glands, which contributes to the formation of stones.

## **Why Each Wrong Option is Incorrect**
- **Option A:** The parotid gland is less commonly affected by stones compared to the submandibular gland. Its saliva has a lower calcium content, and its duct (Stensen's duct) has a more direct path to the oral cavity, reducing the likelihood of stone formation.
- **Option C:** The minor salivary glands are numerous and scattered throughout the oral cavity but are rarely affected by stones.
- **Option D:** The sublingual gland, while capable of producing stones, is much less commonly affected than the submandibular gland.

## **Clinical Pearl / High-Yield Fact**
A key clinical point to remember is that patients with salivary gland stones often present with pain and swelling of the gland, especially during meals when saliva production increases. A classic clinical correlation is the association of sialolithiasis with dehydration and certain dietary habits.

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