## Core Concept
The question tests knowledge of the anatomy of heart valves, specifically the description of their leaflets. Heart valves have cusps or leaflets that open and close to regulate blood flow. The main valves in question are the tricuspid, pulmonary, mitral, and aortic valves.

## Why the Correct Answer is Right
The correct answer, the **tricuspid valve**, has three leaflets described as anterior, left, and right. This valve is located between the right atrium and the right ventricle. Its three leaflets (anterior, posterior - often referred to as left, and septal - often referred to as right) allow for blood flow from the right atrium into the right ventricle while preventing backflow.

## Why Each Wrong Option is Incorrect
- **Option A:** The **pulmonary valve** has three cusps (anterior, left, and right), but the question seems to point towards a valve with leaflets commonly described in a specific manner. However, its description matches but let's evaluate other options.
- **Option B:** The **mitral valve** has two leaflets, an anterior (or anterior-medial) and a posterior (or posterior-lateral), which doesn't match the "anterior, left and right" description.
- **Option C:** The **aortic valve** also has three cusps (right, left, and non-coronary or posterior), which could fit a description but not exactly "anterior, left and right" in conventional terms.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the **tricuspid valve** is the atrioventricular valve on the right side of the heart, crucial for separating the right atrium and ventricle. Its leaflets can be affected in conditions like endocarditis or rheumatic heart disease, leading to significant clinical issues.

## Correct Answer Line
**Correct Answer: B. Tricuspid.**