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
Norplant 1 is expected to be effective up to: 
Select and explain. 
A. 2 years, B. 5 years, C. 7 years, D. 9 years
B: 5 years
Answer: B: 5 years 
Explanation: Norplant 1 contains 6 silastic capsules of which each contains 36 microgram of levonorgestrel. It is expected to be effective for up to 5 years. Ref: Shaw's Textbook of Gynaecology, 12th Edition, Page 179.