3. Heating oil (with an adjustable flowrate of F2) is used to maintain the temperature in a fermentation unit using a feedback control strategy. The cold feed broth sporadically enters the fermentation tank with a flowrate of F1. The exit flowrate of the fermented broth (F3) cannot be adjusted, but its temperature can be measured. Which block diagram corresponds to this process? (circle answer) (A) T Fi controller valve setpoint process T Exit stream F3 F1 F2 T controller valve process setpoint Exit stream (B) T (C) F3 T T F2 controller valve process setpoint Exit stream F3 F2 (D) T T F1 setpoint controller valve process Exit stream What is the sign of the gain between F2 and the temperature (T) of the exit stream? What is the sign of the gain between F1 and the temperature (T) of the exit stream? If a feedforward control strategy is used instead, what would change in the control loop? manipulated variable measured variable 4. Which of the following statements are FALSE? a) Feedback and feedforward control both require a measured variable. b) The process variable to be controlled is measured in feedback control. c) Feedforward control can provide perfect control; that is, the output can be kept at its desired value, even with an imperfect process model or disturbances. d) Feedback control can be combined with feedforward control to reduce drift in the setpoint.