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
The number of muscle fibers innervated by a motor axon is smallest in 
Select and explain. 
A. Gastrocnemius, B. Orbicularis oculi, C. Single unit smooth muscle, D. Soleus
B: Orbicularis oculi
Answer: B: Orbicularis oculi 
Explanation: The extraocular and hand muscles have an innervations ratio of 3 to 6 whereas gastrocnemius and back muscle has a ratio of 2000.(Refer Medical Physiology by Guyton & Hall, 12th edition, page no: 96)