Answer: b) Professional
Step-by-step explanation:
Think tank is described as the institute that conducts research as well as advocacy oriented subjects.These research institute are concerned with various subjects like political techniques and methods, policies, technological topics , economics and many more.
Analysis and research performed by think tanks are considered to be professional as they engage advocacy policy and research activity profession .
Other options are incorrect because science , politics and economics are the subjects on which research are conducted in this profession.Thus, the correct option is option(b).