This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Development period- week 1,2,3,4, Subject name: Anatomy
[{'content': 'Foldings of embryo occurs at:- \nSelect and explain. \nA. 3rd week, B. 4th week, C. 5th week, D. 6th week', 'role': 'user'}, {'content': 'Answer: A \nExplanation: At the end of 3rd week the embryonic area shows the development of head fold, tail fold and two lateral folds. These folds conve the flattened germ disc to cylindrical embryo.', 'role': 'assistant'}]