Number of teeth seen on X-ray at birth:

**Core Concept**
The development of teeth, also known as odontogenesis, begins in the embryonic stage, and by birth, some teeth are already visible on an X-ray. This is related to the **primary dentition** and the timeline of tooth eruption and development.

**Why the Correct Answer is Right**
At birth, the **primary teeth** are at various stages of development. Typically, around 24 to 28 teeth buds are present, but not all are visible on an X-ray. The correct answer reflects the average number of teeth that can be seen radiographically at this stage, considering the usual development timeline.

**Why Each Wrong Option is Incorrect**
**Option A:** This option underestimates the number of teeth that can be visible.
**Option B:** Overestimates, as not all primary teeth are developed enough to be visible on an X-ray at birth.
**Option D:** Significantly overestimates, as this number exceeds the total number of primary teeth.

**Clinical Pearl / High-Yield Fact**
Remember, the first primary tooth typically erupts when the child is about 6 months old, but on an X-ray, more teeth can be seen before they erupt, aiding in the diagnosis of dental developmental issues.

**Correct Answer:** Correct Answer: C.