**Core Concept**
Serous demilunes are a type of histological feature characteristic of serous acinar cells in certain salivary glands. They are formed by the invagination of the apical surface of the acinar cells, creating a crescent-shaped structure. This phenomenon is essential for the secretion and storage of saliva.

**Why the Correct Answer is Right**
The submandibular gland is a mixed-type salivary gland, primarily composed of both serous and mucous acinar cells. The serous demilunes in the submandibular gland are a distinctive feature, allowing for the efficient secretion of enzymes and proteins necessary for digestion. The presence of serous demilunes in the submandibular gland enables the gland to produce a high volume of serous saliva, which is rich in enzymes such as amylase and lipase. This characteristic is not as pronounced in other salivary glands, such as the parotid or sublingual glands, or in the pituitary gland, which is a neuroendocrine gland.

**Why Each Wrong Option is Incorrect**
**Option A:** The parotid gland is primarily composed of serous acinar cells but lacks the characteristic serous demilunes found in the submandibular gland.
**Option C:** The sublingual gland is primarily a mucous gland, with mucous acinar cells, and does not exhibit the serous demilunes characteristic of the submandibular gland.
**Option D:** The pituitary gland is a neuroendocrine gland that produces hormones, such as prolactin and growth hormone, rather than saliva, and therefore lacks serous demilunes.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the submandibular gland's unique histological features, including serous demilunes, contribute to its high enzyme content and secretory function. This knowledge can aid in the understanding of salivary gland disorders and the clinical presentation of conditions such as Sjögren's syndrome.

**✓ Correct Answer: B. Submandibular**