**Core Concept**
Calcification of the aortic valve is a pathological process characterized by the deposition of calcium salts on the valve leaflets. This can lead to aortic stenosis, a condition where the valve narrows, obstructing blood flow from the left ventricle to the aorta.

**Why the Correct Answer is Right**
Calcification of the aortic valve is often associated with age-related wear and tear, leading to the activation of osteoblasts and the deposition of calcium phosphate on the valve surface. This process is also linked to inflammatory conditions such as rheumatoid arthritis and systemic lupus erythematosus, which can trigger an autoimmune response that leads to calcification. Additionally, conditions like bicuspid aortic valve can increase the risk of calcification due to increased turbulence and stress on the valve.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as calcification of the mitral valve is a different condition, often associated with mitral annular calcification, which is a degenerative process that leads to calcium deposition on the mitral valve annulus.
**Option B:** This option is incorrect as calcification of the pulmonary valve is rare and usually associated with congenital heart disease or rheumatic fever.
**Option C:** This option is incorrect as calcification of the tricuspid valve is also rare and often associated with rheumatic fever or congenital heart disease.

**Clinical Pearl / High-Yield Fact**
It's essential to note that calcification of the aortic valve is a common cause of aortic stenosis, which can lead to symptoms such as chest pain, shortness of breath, and syncope. Aortic stenosis is a significant cause of morbidity and mortality in elderly populations.

**Correct Answer:** D.