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
In which of the following transition meiosis occurs 
Select and explain. 
A. Primary to secondary spermatocyte, B. Second spermatocyte to globular spermatid, C. Germ cells to spermatogonium, D. Spermatogonium to primary spermatocyte
A: Primary to secondary spermatocyte
Answer: A: Primary to secondary spermatocyte 
Explanation: Transition meiosis

Transition from mitosis to meiosis
The spermatogonia undergo mitosis to form the primary  spermatocytes, which then enter first meiotic division. They rest for 22 days and then rapidly complete the first meiotic division to form secondary spermatocytes.
During second meiotic division secondary spermatocyte divides into spermatids.