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': 'Promoter sequence is an example for \nSelect and explain. \nA. Cis acting factor, B. Trans acting factor, C. Coactivator, D. Mediator', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Trans acting factors control the expression of cis-regulatory element Cis-regulatory elements are DNA sequences present on the same molecule of DNA (chromosome) as the gene they regulate. E.g. Promoter is a cis-regulated element usually located upstream of the transcribed region. Enhancers are cis-regulatory elements that can be located upstream, downstream, within the introns,', 'role': 'assistant'}]