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: Unknown
Insulin resistance in pregnancy is due to - 
Select and explain. 
A. Estrogen, B. Progesterone, C. HPL, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: All of the above