## Core Concept
The articular surface of a synovial joint is covered by a type of cartilage known as **hyaline cartilage** or **articular cartilage**. This cartilage plays a crucial role in reducing friction during movement and absorbing shocks. The microscopic examination of articular cartilage reveals its unique structure.

## Why the Correct Answer is Right
The correct answer, , indicates that the articular surface is covered by **articular cartilage**. Microscopically, articular cartilage is composed of chondrocytes (cartilage cells) embedded in a matrix that includes collagen fibers, proteoglycans, and water. This composition allows articular cartilage to provide a smooth, lubricated surface for joint movement. The chondrocytes are located in lacunae within the matrix, and the cartilage is avascular, meaning it lacks blood vessels.

## Why Each Wrong Option is Incorrect
* **Option A:** This option is incorrect because it does not accurately describe the microscopic features of articular cartilage.
* **Option B:** This option is incorrect as it does not specifically mention articular cartilage or its characteristic features.
* **Option D:** This option is incorrect because it does not accurately represent the microscopic appearance or composition of articular cartilage.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **articular cartilage** is **avascular**, meaning it does not have a blood supply. This characteristic is crucial for understanding why injuries to articular cartilage can be challenging to heal. The lack of blood vessels limits the delivery of oxygen, nutrients, and cells necessary for repair.

## Correct Answer Line
**Correct Answer: C. articular cartilage.**