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
The most definitive clinical sign of pregnancy is : 
Select and explain. 
A. Ballottement, B. Fetal hea sounds, C. Braxton Hick's contraction, D. Enlarged uterus
B: Fetal hea sounds
Answer: B: Fetal hea sounds 
Explanation: Fetal hea sounds