**Core Concept**
The question is testing knowledge of **infective endocarditis**, specifically the location of vegetations on heart valves. This condition involves the formation of **vegetations** on valve surfaces due to microbial infection.

**Why the Correct Answer is Right**
In infective endocarditis, vegetations can form on either surface of the valve leaflets, but their location can give clues about the type of endocarditis. Vegetations on the **under surface of cusps** are more commonly associated with **acute infective endocarditis**, particularly when caused by highly virulent organisms.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it doesn't specify the correct location of vegetations.
**Option B:** Incorrect as it is not directly related to the specific location of vegetations in question.
**Option C:** Incorrect because it is more commonly associated with a different condition or type of endocarditis.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the location and appearance of vegetations can provide clues about the causative organism and the severity of the infection.

**Correct Answer:** D. Infective endocarditis