This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
Prolactin levels: 
Select and explain. 
A. Lowest in pregnancy, B. Highest during pregnancy, C. Unaffected by pregnancy and lactation, D. Variable in every pregnancy
B: Highest during pregnancy
Answer: B: Highest during pregnancy 
Explanation: Prolactin increases tremendously in pregnancy and this ensures lactation.