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: Gynaecology & Obstetrics
Fetal bradycardia is defined as : 
Select and explain. 
A. Less than 100 beat/min, B. Between 100 and 200 beat/min, C. Less than 120 beat/min, D. Less than 120 beat/min for a period of 15 min of continuous monitoring
D: Less than 120 beat/min for a period of 15 min of continuous monitoring
Answer: D: Less than 120 beat/min for a period of 15 min of continuous monitoring 
Explanation: Less than 120 beat/min for a period of 15 min of continuous monitoring