## Core Concept
Bone density is a measure used to indicate the strength and health of bones. It is often assessed through techniques like dual-energy X-ray absorptiometry (DXA). Bone density can vary based on several factors including age, genetics, and hormonal influences.

## Why the Correct Answer is Right
Cortical bone, also known as compact bone, has a higher density compared to cancellous (trabecular) bone. Cortical bone forms the outer layer of bones and is denser and stronger. This is because cortical bone is composed of tightly packed osteons (haversian systems) which contribute to its high density and structural integrity.

## Why Each Wrong Option is Incorrect
- **Option A:** Cancellous bone, or trabecular bone, has a lower density compared to cortical bone. It is found at the ends of long bones and within the inner layer of bones, having a more porous structure.
- **Option B:** While both types of bone are essential for overall bone health, the question specifically asks for greater bone density, which points towards cortical bone.
- **Option D:** This option might seem plausible but given the context, it does not accurately represent the type of bone with greater density.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **cortical bone** accounts for about 80% of the skeleton's mass but only 20% of its surface area. It plays a crucial role in providing structural support and protection.

## Correct Answer: C. Cortical bone.