**Core Concept**
The spinal cord in infants is a unique anatomical feature that differs from adults. In infants, the spinal cord extends further down the vertebral column than in adults, a phenomenon known as spinal cord elongation. This is due to the continuous growth of the spinal cord and the vertebral column.

**Why the Correct Answer is Right**
In infants, the spinal cord ends at the level of L3, whereas in adults, it typically ends at the level of L1. This difference is due to the fact that the spinal cord grows at a faster rate than the vertebral column, resulting in the cord extending further down the vertebral column in infants. This anatomical feature is essential for pediatricians and neurosurgeons to consider when performing spinal procedures in infants.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is inconsistent with the anatomical features of the spinal cord in infants.
**Option B:** This option is incorrect because it is not supported by anatomical evidence.
**Option C:** This option is incorrect because it is not relevant to the anatomical features of the spinal cord in infants.

**Clinical Pearl / High-Yield Fact**
It is essential for clinicians to remember that the spinal cord ends at a higher level in infants, which can have significant implications for surgical procedures and patient care.

**Correct Answer: D. L3.**