This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
The remnants of Hertwig's epithelial root sheath is known as: 
Select and explain. 
A. Epithelial pearls., B. Epithelial knots., C. Epithelial island., D. Epithelial cell rests.
D: Epithelial cell rests.
Answer: D: Epithelial cell rests. 
Explanation: When root dentin formation is completed, this portion of the basement membrane also disintegrates, as does the entire HERS. After this disintegration of the root sheath, its cells may become the epithelial rests of Malassez. These groups of epithelial cells become located in the mature periodontal ligament and can become cystic, presenting future problems.