This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Transcription, Subject name: Biochemistry
[{'content': 'A highly specific inhibitor that targets the phosphorylation activity of TFIIH is added to an in vitro transcription reaction. Which one of the following steps is most likely to be affected? \nSelect and explain. \nA. Binding of RNA polymerase to promoter sequence, B. Promoter clearance, C. Recruitment of TFIID, D. Open promoter complex formation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most likely to be affected by inhibitor that targets the phosphorylation activity of TFIIH is promoter clearance Transcription factor II H has two activities : Helicase Kinase -Unwinds the DNA -Phosphorylates the TFIIH- Promoter clearance.', 'role': 'assistant'}]