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
Which of the following represents most dangerous situation: 
Select and explain. 
A. Rh + ve mother, who is bearing 2nd Rh -ve child, B. Rh - ve mother, bearing her 2nd Rh + ve child, C. Rh + ye mother, bearing her 1st Rh -ve child, D. Rh — ye mover, bearing her 1st Rh + ye child
B: Rh - ve mother, bearing her 2nd Rh + ve child
Answer: B: Rh - ve mother, bearing her 2nd Rh + ve child 
Explanation: None