## Core Concept
The radial head is one of the ossification centers in the human body. Ossification centers are cartilaginous templates that gradually ossify (or harden into bone) during fetal development and childhood. The timing of ossification for different bones and their parts is crucial for growth and development.

## Why the Correct Answer is Right
The radial head, which is part of the radius bone in the forearm, begins to ossify around **4-6 years** of age. This process is part of endochondral ossification, where a cartilage template is gradually replaced by bone tissue. The timing of this process is critical for the proper development and function of the elbow joint.

## Why Each Wrong Option is Incorrect
- **Option A:** Typically, the ossification of the radial head starts later than 1 year of age.
- **Option B:** While close, the typical age range for the start of radial head ossification is a bit later than 3 years.
- **Option D:** The ossification of the radial head usually begins earlier than 10 years of age.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the radial head ossifies around **4-6 years** of age. This knowledge is essential for pediatricians and orthopedic surgeons to assess growth and development and to diagnose potential issues such as fractures or growth abnormalities in children.

## Correct Answer: C. 4-6 years.