**Core Concept**
Monogenic inheritance refers to a pattern of inheritance where a single gene mutation causes a specific genetic disorder. This type of inheritance is often associated with autosomal dominant or autosomal recessive patterns.

**Why the Correct Answer is Right**
Sickle cell anemia is a classic example of a monogenic disorder, resulting from a point mutation in the HBB gene that codes for the beta-globin subunit of hemoglobin. This mutation leads to the production of sickle hemoglobin (HbS), which causes red blood cells to take on a characteristic sickle shape. The HBB gene is located on the short arm of chromosome 11 (11p15.4). The autosomal recessive pattern of inheritance means that an individual must inherit two copies of the mutated gene (one from each parent) to express the disease.

**Why Each Wrong Option is Incorrect**
**Option A:** Cystic fibrosis is a polygenic disorder, meaning it is influenced by multiple genes rather than a single gene mutation. It is caused by mutations in the CFTR gene, but the disease is influenced by multiple genetic and environmental factors.
**Option B:** Diabetes mellitus is a polygenic disorder, influenced by multiple genes, with a strong environmental component. While there are monogenic forms of diabetes, such as maturity-onset diabetes of the young (MODY), the question is asking for a classic example of a monogenic disorder.
**Option C:** Hypertension is a complex disorder influenced by multiple genetic and environmental factors, and is not typically considered a monogenic disorder.

**Clinical Pearl / High-Yield Fact**
Remember that monogenic disorders often have a clear family history, with affected individuals often having a parent or sibling with the same condition.

**Correct Answer: C. Sickle cell anemia is a classic example of a monogenic disorder, resulting from a point mutation in the HBB gene that codes for the beta-globin subunit of hemoglobin.**