**Core Concept**
Basal lamina, also known as the basement membrane, is a thin, fibrous structure that separates epithelial cells from the underlying connective tissue. It is composed of various molecules that provide structural support, maintain tissue integrity, and regulate cellular interactions.

**Why the Correct Answer is Right**
The basal lamina is primarily composed of collagen type IV, laminin, and nidogen/entactin. These molecules form a network of fibers that anchor the basal lamina to the underlying basement membrane and provide a site for cell attachment, migration, and differentiation. The basal lamina also contains various enzymes, such as glycosaminoglycans and proteoglycans, that regulate its structure and function.

**Why Each Wrong Option is Incorrect**
**Option A:** Basal lamina is primarily composed of collagen type I, which is incorrect as collagen type I is a major component of the dermal collagen layer, not the basal lamina.
**Option B:** Basal lamina is primarily composed of laminin alone, which is incorrect as the basal lamina is a complex structure composed of multiple molecules, including collagen type IV, laminin, and nidogen/entactin.
**Option C:** Basal lamina is primarily composed of glycosaminoglycans, which is incorrect as glycosaminoglycans are present in the basal lamina but are not its primary component.

**Clinical Pearl / High-Yield Fact**
The basal lamina plays a crucial role in maintaining tissue integrity and regulating cellular interactions. Alterations in basal lamina composition or structure can lead to various diseases, including muscular dystrophies, nephrotic syndrome, and diabetes mellitus.

**Correct Answer: C. Laminin**