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
During cap stage signalling in odontogenic epithelium is done by? 
Select and explain. 
A. Dental follicle, B. Enamel knot, C. Dental papilla, D. Inner enamel epithelium
B: Enamel knot
Answer: B: Enamel knot 
Explanation: None