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
Electric nerve tester detects pain by stimulating which nerve fibres (OR) Sharp, shooting pain in reversible pulpitis indicates stimulation of (OR) In pulp hyperemia which nerve fibers are stimulated 
Select and explain. 
A. A alpha, B. A beta, C. A delta, D. C fibres
C: A delta
Answer: C: A delta 
Explanation: None