**Core Concept**
The management of deep caries (<2 mm of dentine remaining) requires careful consideration of the remaining dentine thickness to prevent bacterial invasion and potential pulpal exposure. The use of resin composite restoration is a conservative approach to restore the tooth structure while minimizing the risk of further caries progression.

**Why the Correct Answer is Right**
In deep caries (<2 mm of dentine remaining), the primary concern is the potential for bacterial invasion through the remaining dentine. Resin composite restoration is an ideal option as it allows for the removal of the infected dentine, sealing of the remaining dentine surface, and restoration of the tooth structure. This approach helps to prevent further caries progression and preserves the remaining tooth structure.

• The resin composite material has a low modulus of elasticity, allowing for minimal stress on the remaining dentine and reducing the risk of fracture.
• The use of adhesive systems enables a strong bond between the resin composite and the remaining dentine, ensuring the longevity of the restoration.
• Resin composite restorations can be easily polished, reducing the risk of secondary caries and facilitating oral hygiene.

**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect as it does not address the primary concern of bacterial invasion through the remaining dentine. A full-coverage crown may not be necessary in this scenario, and it may not provide adequate support for the remaining tooth structure.

**Option B:**
This option is incorrect as it does not provide a conservative approach to restore the tooth structure. Extraction may be considered in cases of severe caries or pulp exposure, but it is not the first line of management for deep caries (<2 mm of dentine remaining).

**Option C:**
This option is incorrect as it does not address the need for removal of the infected dentine and sealing of the remaining dentine surface. A simple filling may not provide adequate support for the remaining tooth structure and may not prevent further caries progression.

**Clinical Pearl / High-Yield Fact**
When managing deep caries (<2 mm of dentine remaining), it is essential to consider the remaining dentine thickness and the potential for bacterial invasion. A conservative approach using resin composite restoration can help to prevent further caries progression and preserve the remaining tooth structure.

**Correct Answer:** C.