**Core Concept**
Looser's zones are characteristic radiological findings in conditions associated with bone resorption and remodeling. These zones represent areas of cystic bone resorption with thinning of the cortical bone, typically seen in osteomalacia and rickets.

**Why the Correct Answer is Right**
Looser's zones are a result of abnormal bone remodeling due to impaired mineralization. They are most commonly seen in conditions of phosphate deficiency or impaired vitamin D metabolism, leading to softening of the bones (osteomalacia). The pathophysiology involves an imbalance in the calcium-phosphate product, leading to impaired bone mineralization and subsequent resorption.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Looser's zones are not typically seen in conditions of osteoporosis, which is characterized by a decrease in bone density without an increase in bone resorption.

**Option B:** This option is incorrect because Paget's disease is a localized skeletal disorder that involves bone resorption and subsequent new bone formation, but it does not typically present with Looser's zones.

**Option C:** This option is incorrect because fibrous dysplasia is a genetic disorder that affects bone development, but it does not typically present with Looser's zones.

**Clinical Pearl / High-Yield Fact**
Looser's zones are a classic radiological finding in osteomalacia, and their presence should prompt evaluation for phosphate deficiency or impaired vitamin D metabolism.

**Correct Answer:** C.