**Core Concept**
Prolactin is a hormone secreted by the pituitary gland, and understanding its embryological origin is crucial for grasping the pathophysiology of prolactinomas and other pituitary disorders. The development of the pituitary gland involves a complex interplay of embryonic tissues and signaling pathways.

**Why the Correct Answer is Right**
The pituitary gland, also known as the hypophysis, develops from two distinct embryonic sources: the ectodermal Rathke's pouch and the neuroectodermal infundibulum. Rathke's pouch forms the anterior pituitary, while the infundibulum gives rise to the posterior pituitary. Prolactin-secreting cells, specifically lactotrophs, originate from the anterior pituitary gland, which develops from Rathke's pouch.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct embryonic origin of the prolactin-secreting gland.
**Option B:** This option is incorrect because it is too vague and does not accurately describe the development of the pituitary gland.
**Option C:** This option is incorrect because it is a general term that encompasses the development of various parts of the brain, but it is not specific to the origin of the prolactin-secreting gland.

**Clinical Pearl / High-Yield Fact**
The pituitary gland develops from two distinct embryonic sources, and understanding this embryological origin is crucial for diagnosing and managing pituitary disorders, such as prolactinomas. The anterior pituitary gland, which secretes prolactin, develops from Rathke's pouch, while the posterior pituitary gland develops from the infundibulum.

**Correct Answer: C. Ectodermal Rathke's pouch.**