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
Intermediate filaments of epithelial cells is/are: 
Select and explain. 
A. Cytokeratin, B. Microfilaments, C. Microfibrils., D. All of the above
A: Cytokeratin
Answer: A: Cytokeratin 
Explanation: They are called intermediate filaments as their diameter is intermediate between larger microtubules and smaller microfilaments.