Temperature control of an exothermic chemical reaction taking place in a CSTR is done with the help of cooling water flowing in a jacket around the reactor. The types of valve and controller action to be recommended are

• A. air to open valve with the controller direct acting.
• B. air to close valve with the controller indirect acting.
• C. air to open valve with the controller indirect acting.
• D. air to close valve with the controller direct acting.