**Core Concept**
The question requires knowledge of the American Dental Association (ADA) Clinical Considerations for Sealants (CCS) guidelines, specifically for managing early caries lesions (ICDAS score 2) in patients at extreme risk of caries progression.

**Why the Correct Answer is Right**
For patients at extreme risk, the ADA CCS recommends using a sealant or restoration material that is highly effective in preventing caries progression. In this case, the recommended material is a **resin-modified glass-ionomer cement (RMGIC)**. RMGIC provides a durable, fluoride-releasing seal that can help prevent the progression of early caries lesions. The fluoride release can also help to remineralize the tooth structure, reducing the risk of further caries progression.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a recommended material for managing early caries lesions in extreme risk patients.
**Option B:** This option is incorrect because it may not be suitable for managing early caries lesions in extreme risk patients, as it may not provide a durable or fluoride-releasing seal.
**Option C:** This option is incorrect because it may not be the most effective material for managing early caries lesions in extreme risk patients.

**Clinical Pearl / High-Yield Fact**
When managing early caries lesions in extreme risk patients, it's essential to use a material that provides a durable, fluoride-releasing seal to prevent caries progression and promote remineralization of the tooth structure.

**Correct Answer: A. Resin-modified glass-ionomer cement (RMGIC)**