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: Biochemistry
[{'content': 'All steps of N- glycosylation occur in ER except \nSelect and explain. \nA. Dolichol synthesis, B. Glycosyl transferase, C. Protein- oligosacharide transferase, D. Final trimming', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. Final trimming', 'role': 'assistant'}]