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: Medicine
A 25-years old female developed secondary amenorrhoea of 6 month duration. Even after administration of oestrogen and progesterone for two weeks, there was no vaginal bleeding. The underlying cause could be in the - 
Select and explain. 
A. Pituitary glands, B. Hypothalamus, C. Uterus, D. Ovary
C: Uterus
Answer: C: Uterus 
Explanation: None