This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Extrafiisal fibre innervated by 
Select and explain. 
A. Ia, B. lb, C. Aa, D. Ass
C: Aa
Answer: C: Aa 
Explanation: Extrafusal fibers are innervate by A-alfa motor neurons They are myelinated and fast conducting Ref:Guyton and Hall textbook of medical physiology 12th edition,page number:769,770,771