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
A 28-year-old lady is suspected to have the polycystic ovarian disease. The sample for testing LH & FSH are best taken on the following days of the menstrual cycle 
Select and explain. 
A. 10-Aug, B. 4-Jan, C. 13-15, D. 24-26
B: 4-Jan
Answer: B: 4-Jan 
Explanation: Serum FSH concentrations vary signiﬁcantly across the cycle, hence serum FSH concentration is best obtained during the early follicular phase (cycle day 2–4)