This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
The duration of atrial systole is 
Select and explain. 
A. 0.80 second, B. 0.57 second, C. 0.11 second, D. 0.44 second
C: 0.11 second
Answer: C: 0.11 second 
Explanation: The duration of each of the hea sounds is slightly more than 0.10 second, with the first sound about 0.14 second and the second about 0.11 second. Ref: Guyton and Hall textbook of medical physiology 13th edition. Page: 119