This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Contraception, Subject name: Gynaecology & Obstetrics
The progestin present in Sino-Implant II is 
Select and explain. 
A. Etonogestrel, B. Levonorgestrel, C. Norethisterone, D. Desogestrel
B: Levonorgestrel
Answer: B: Levonorgestrel 
Explanation: The Sino-Implant II is a less expensive two-rod levonorgestrel system manufactured in China and available in several countries. It is effective for 4 yearsReference: Novak's gynaecology; 14th edition; Chapter 10; Family planning