**Core Concept**
The eruption of primary teeth in infants is a significant developmental milestone. The sequence of eruption is crucial for understanding normal dental development and potential issues such as delayed or premature eruption.

**Why the Correct Answer is Right**
The primary incisors, specifically the central incisors, are the first teeth to erupt in an infant. This is due to their location in the anterior (front) region of the mouth, which allows for easy access to the oral cavity and facilitates their eruption. The central incisors are followed by the lateral incisors and then the first molars. The eruption of these teeth is influenced by the development of the dental lamina and the formation of the dental follicle, which eventually gives rise to the tooth.

**Why Each Wrong Option is Incorrect**
**Option A:** Not applicable (this option is missing).
**Option B:** Upper first molars – These teeth erupt later in the primary dentition, typically between 12-16 months of age.
**Option C:** Canines – These teeth erupt even later than the first molars, usually between 16-22 months of age.
**Option D:** Lower first molars – These teeth erupt after the lower central incisors and are part of the primary dentition.

**Clinical Pearl / High-Yield Fact**
The eruption of primary teeth is influenced by various factors, including genetics, nutrition, and overall health. It is essential for pediatricians and dentists to monitor the eruption of primary teeth to identify potential issues such as delayed or premature eruption, which can be indicative of underlying health problems.

**Correct Answer:** C. Canines are not the first incisors to erupt.