**Core Concept**
Anorganic bone refers to a bone that has been stripped of its organic components, primarily collagen, leaving behind a scaffold of hydroxyapatite crystals. This process is achieved through the use of acidic solutions, such as hydrochloric acid or nitric acid, which dissolve the organic matrix while preserving the inorganic mineral content.

**Why the Correct Answer is Right**
The correct answer is a type of bone substitute that is used in orthopedic and dental procedures to promote bone growth and integration. Anorganic bone is often used in conjunction with osteoinductive agents, such as bone morphogenetic proteins (BMPs), to stimulate the formation of new bone tissue. The inorganic mineral content of anorganic bone provides a scaffold for cell attachment and differentiation, allowing for the growth of new bone.

**Why Each Wrong Option is Incorrect**
**Option A:** Cortical bone is a dense, compact layer of bone tissue that forms the outer surface of most bones. While cortical bone is an important component of bone structure, it is not an example of anorganic bone.

**Option B:** Bone graft is a type of tissue that is used to repair or replace damaged bone tissue. While bone grafts can be made from anorganic bone, the term "bone graft" is too broad to be a correct answer.

**Option C:** Hydroxyapatite is a type of calcium phosphate crystal that is a major component of bone tissue. While hydroxyapatite is present in anorganic bone, the correct answer is a more specific type of bone substitute.

**Clinical Pearl / High-Yield Fact**
Anorganic bone is a type of bone substitute that is often used in orthopedic and dental procedures to promote bone growth and integration. It is particularly useful in procedures where there is a need for a scaffold to support new bone tissue.

**Correct Answer:** C.