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
Which of the following are situated away from the coding region 
Select and explain. 
A. Promoter, B. Enhancer, C. Operator, D. All of these
D: All of these
Answer: D: All of these 
Explanation: Structural genes are present in coding region. Rest all genes, like promoter gene, operator gene, regulatory gene (enhancer/repressor), are present away from coding region.