**Core Concept**
Paget's disease of bone is a chronic focal skeletal disorder characterized by abnormal bone remodeling, leading to bone deformity, pain, and increased risk of osteosarcoma. It is a localized disorder of bone metabolism, involving an imbalance between bone resorption and bone formation.

**Why the Correct Answer is Right**
The condition is often referred to as osteitis deformans, reflecting the inflammation and bone deformation aspects of the disease. This name was coined by Sir James Paget, the physician who first described the condition in 1877. The disease is a result of an abnormal osteoclast-osteoblast interaction, where osteoclasts excessively resorb bone, leading to an imbalance in bone remodeling.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because osteogenesis imperfecta is a different genetic disorder characterized by brittle bones and skeletal fragility.
* **Option B:** This option is incorrect because fibrous dysplasia is a non-neoplastic disorder involving the replacement of normal bone with fibrous tissue, leading to bone deformity.
* **Option C:** This option is incorrect because osteoporosis is a systemic bone disorder characterized by decreased bone density and increased risk of fractures.

**Clinical Pearl / High-Yield Fact**
Paget's disease of bone can be diagnosed using imaging studies such as X-rays, CT scans, or bone scans, which show characteristic features of bone deformation and increased bone turnover.

**Correct Answer:** C. Osteitis deformans.