Donovanosis is caused by
**Core Concept**
Donovanosis, also known as granuloma inguinale, is a **sexually transmitted infection** caused by a specific bacterium. The underlying principle being tested here involves the identification of the causative agent of this disease.
**Why the Correct Answer is Right**
The correct answer is *Klebsiella granulomatis*, formerly known as *Calymmatobacterium granulomatis*. This bacterium is a **Gram-negative** coccobacillus that infects the skin and mucous membranes, leading to the formation of ulcerative lesions.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it is not the causative agent of donovanosis.
**Option B:** Incorrect as it is associated with a different condition.
**Option C:** Incorrect because it does not cause donovanosis.
**Option D:** Incorrect as the actual causative agent is *Klebsiella granulomatis*.
**Clinical Pearl / High-Yield Fact**
Donovanosis is typically characterized by painless, beefy-red ulcers that bleed easily, and it is more common in tropical and subtropical regions.
**Correct Answer:** D. Klebsiella granulomatis.