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: Physiology
All of the following are true about cardiac muscles, EXCEPT: 
Select and explain. 
A. Abundant mitochondria are present., B. Has high content of myoglobin, C. 10% energy is provided by anerobic metabolism, D. None of the above
C: 10% energy is provided by anerobic metabolism
Answer: C: 10% energy is provided by anerobic metabolism 
Explanation: Mammalian heas have an abundant blood supply, numerous mitochondria, and a high content of myoglobin, a muscle pigment that can function as an O2 storage mechanism. Normally, less than 1% of the total energy liberated is provided by anaerobic metabolism. Ref: Ganong's Review of Medical Physiology 23rd edition, Chapter 5.