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
Delta waves of Electroencephalogram have frequency of: 
Select and explain. 
A. More than 14 cycles per second, B. Between 8 and 13 cycles per second, C. Less than 3.5 cycles per second, D. Between 4 and 7 cycles per second
C: Less than 3.5 cycles per second
Answer: C: Less than 3.5 cycles per second 
Explanation: None