**Core Concept**
Diphtheria is a bacterial infection caused by Corynebacterium diphtheriae, characterized by the formation of a toxin-producing pseudomembrane on the tonsils and throat. This toxin, diphtheria toxin, is responsible for the systemic complications of the disease.

**Why the Correct Answer is Right**
The diphtheria toxin inhibits protein synthesis by inactivating the elongation factor-2 (EF-2), a crucial factor in translating messenger RNA to protein. This leads to the shutdown of protein synthesis in host cells, causing cell death and tissue damage. The toxin also triggers an immune response, leading to inflammation and the release of toxic mediators.

**Why Each Wrong Option is Incorrect**
**Option A:** Not provided.
**Option B:** Not provided.
**Option C:** Not provided.

**Clinical Pearl / High-Yield Fact**
To diagnose diphtheria, a throat swab should be sent for Gram stain and culture. The presence of a pseudomembrane on the tonsils and throat, along with a history of contact with an infected person, supports the diagnosis.

**Correct Answer:** Not provided.