**Core Concept**
Pseudoparalysis in infants refers to a condition where a child appears to be paralyzed due to pain or discomfort, often caused by a specific underlying condition. This condition highlights the importance of distinguishing between actual paralysis and pseudoparalysis in infants, as the latter can be a sign of a serious underlying issue.

**Why the Correct Answer is Right**
The most common cause of pseudoparalysis in infants is congenital dislocation of the hip (CDH), also known as developmental dysplasia of the hip (DDH). In CDH, the hip joint is not properly formed, leading to instability and pain in the hip. This pain can cause the infant to refuse to move the affected leg, giving the appearance of paralysis. The femoral head is not properly seated in the acetabulum, leading to discomfort and subsequent pseudoparalysis.

**Why Each Wrong Option is Incorrect**
* **Option A:** Erb's palsy, a condition caused by injury to the brachial plexus, typically presents with weakness or paralysis of the arm, not pseudoparalysis.
* **Option B:** Spinal cord injury would typically present with actual paralysis, not just pseudoparalysis due to pain.
* **Option D:** Osteogenesis imperfecta, a condition characterized by brittle bones, may present with fractures and pain, but not typically pseudoparalysis.

**Clinical Pearl / High-Yield Fact**
In infants, pseudoparalysis is often a sign of a hip disorder, so always examine the hips in infants with limb weakness or refusal to move a limb.

**Correct Answer:** C.