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: Physiology
In a foetus, thyroxine secretion begins by? 
Select and explain. 
A. 3rd month, B. 8th week, C. 10th to 12th weeks, D. 9th month
C: 10th to 12th weeks
Answer: C: 10th to 12th weeks 
Explanation: Thyroxine secretion begins by 10th to 12th weeks. Glucagon secretion begins by 8th week. Insulin containing granules can be identified in the human foetal pancreas by 9 to 10 weeks. and insulin in foetal plasma is detectable at 12 weeks. Ref: Williams Obstetrics, 22/e, Page 108 ; Dutta Obstetrics 6/e, Page 43