**Core Concept**
Mitral valve prolapse (MVP) is a condition characterized by the abnormal upward displacement of the mitral valve leaflets into the left atrium during systole, often associated with a midsystolic click and a late systolic murmur. This occurs due to the elongation and redundancy of the mitral valve leaflets, which may be congenital or acquired.

**Why the Correct Answer is Right**
The characteristic feature of mitral valve prolapse is the presence of a midsystolic click, which is the sound of the mitral valve leaflets suddenly snapping into place as they prolapse into the left atrium. This is often accompanied by a late systolic murmur due to mitral regurgitation. The prolapsing leaflets can also cause a palpable systolic thrill and can be associated with mitral stenosis or mitral regurgitation.

**Why Each Wrong Option is Incorrect**
* **Option A:** Mitral valve stenosis is characterized by the narrowing of the mitral valve orifice, leading to obstruction of blood flow from the left atrium to the left ventricle. It is not associated with mitral valve prolapse.
* **Option B:** Tricuspid regurgitation is a condition characterized by the backflow of blood from the right ventricle to the right atrium due to an incompetent tricuspid valve. It is not related to mitral valve prolapse.
* **Option C:** Aortic stenosis is a condition characterized by the narrowing of the aortic valve orifice, leading to obstruction of blood flow from the left ventricle to the aorta. It is not associated with mitral valve prolapse.

**Clinical Pearl / High-Yield Fact**
A key clinical feature of mitral valve prolapse is the presence of a midsystolic click, which can be auscultated at the apex with the patient in a left lateral decubitus position. This is a high-yield fact for exam purposes.

**Correct Answer:** C.