**Core Concept**
The American Academy of Pediatric Dentistry (AAPD) and the American Dental Association (ADA) recommend regular dental check-ups and radiographic examinations to monitor the development of dental caries in high-risk children. Bitewing radiographs are a crucial tool in detecting interproximal caries, especially in areas not visible during a visual examination.

**Why the Correct Answer is Right**
The correct answer is based on the guidelines from the AAPD and ADA, which suggest that high-risk children should have bitewing radiographs taken every 6 months to monitor the progression of dental caries. This frequency helps in early detection and prevention of interproximal caries, which can lead to more severe dental problems and increased treatment costs.

**Why Each Wrong Option is Incorrect**

* **Option A:** This option is incorrect as it does not follow the recommended frequency for high-risk children. Taking bitewing radiographs less frequently may lead to delayed detection of interproximal caries.
* **Option B:** This option is incorrect as it suggests a frequency that is too low for high-risk children. Taking bitewing radiographs only once a year may not be sufficient to detect the progression of dental caries.
* **Option C:** This option is incorrect as it suggests a frequency that is too high for high-risk children. Taking bitewing radiographs every 3 months may lead to radiation exposure and increased costs without providing significant benefits.

**Clinical Pearl / High-Yield Fact**
High-risk children should have bitewing radiographs taken every 6 months to monitor the progression of dental caries. This frequency helps in early detection and prevention of interproximal caries, which can lead to more severe dental problems and increased treatment costs.

**Correct Answer:** D.