**Core Concept**
The current recommendation for systemic fluoride supplements aims to prevent dental caries in children residing in areas with naturally low water fluoride levels. This is achieved by supplementing fluoride to the child's diet, which helps in the mineralization of tooth enamel and makes it more resistant to acid attacks from plaque bacteria.

**Why the Correct Answer is Right**
The American Dental Association (ADA) and the American Academy of Pediatric Dentistry (AAPD) recommend systemic fluoride supplements for children residing in areas with water fluoride levels below 0.7 parts per million (ppm). This is because fluoride is essential for the proper development of teeth and bones. The supplementation is usually recommended until the child is at least 16 to 17 years old, or until the water fluoride level in their area reaches 0.7 ppm. This is because fluoride continues to play a role in dental health throughout childhood and adolescence.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the recommended age for fluoride supplementation may vary depending on the individual child's risk for dental caries and the fluoride levels in their water supply. However, it is generally recommended to continue supplementation until the child is at least 16 to 17 years old.
* **Option B:** This option is incorrect because the recommended age for fluoride supplementation is not until the child is 18 years old. While fluoride continues to play a role in dental health throughout childhood and adolescence, the ADA and AAPD recommend stopping supplementation by the time the child is at least 16 to 17 years old.
* **Option C:** This option is incorrect because it is not a recommended age for stopping fluoride supplementation. The recommended age for stopping supplementation is until the child is at least 16 to 17 years old, not until they are 14 years old.

**Clinical Pearl / High-Yield Fact**
It's essential to note that children living in areas with naturally high water fluoride levels should not receive systemic fluoride supplements, as excessive fluoride intake can lead to fluorosis and other health problems. This is a critical consideration for pediatricians and dentists when recommending fluoride supplementation for children.

**Correct Answer: C. 14 years old**