**Core Concept**
Pelkan spur is a radiological finding associated with a specific metabolic disorder affecting bone health. It is characterized by a peculiar appearance on radiographs, which is a result of abnormal bone mineralization.

**Why the Correct Answer is Right**
Pelkan spur is a classical finding in scurvy, a disease caused by vitamin C deficiency. In scurvy, the body's inability to produce adequate collagen leads to impaired bone mineralization, resulting in the formation of abnormal bony projections or spurs. Specifically, Pelkan spur is a radiographic sign that appears as a small, irregular bone projection or spur, typically seen at the metaphyseal end of long bones. This occurs due to the abnormal deposition of calcium salts in the damaged bone matrix.

**Why Each Wrong Option is Incorrect**
**Option A:** Rickets, another metabolic bone disorder, is characterized by softening of bones in children due to vitamin D deficiency. Although rickets shares some similarities with scurvy, Pelkan spur is not a characteristic finding in rickets.

**Option C:** Hemophilia is a genetic disorder affecting blood clotting, which can lead to joint and bone abnormalities. However, Pelkan spur is not a specific radiological feature associated with hemophilia.

**Option D:** This option is incorrect because Pelkan spur is not seen in all the listed conditions.

**Clinical Pearl / High-Yield Fact**
Pelkan spur is an important radiological sign that can help diagnose scurvy, a condition that can have a wide range of clinical manifestations, including fatigue, malaise, and impaired wound healing.

**✓ Correct Answer: B. Scurvy**