This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Basics of genetics, Subject name: Biochemistry
Lac operon is: 
Select and explain. 
A. Repressor, B. Inducer, C. Operator, D. Activator
B: Inducer
Answer: B: Inducer 
Explanation: Lac operon Inducible operon Because at first it is suppressed most of the times If required it can be induced/Activated.