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: Anatomy
What tissue from the implanting embryo directly interfaces with the endometrial connective tissue? 
Select and explain. 
A. Inner cell mass, B. Extra embryonic mesoderm, C. Epiblast, D. Syncytiotrophoblast
D: Syncytiotrophoblast
Answer: D: Syncytiotrophoblast 
Explanation: None