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) F3 F2 T FL T controller valve process setpoint Exit stream F3 F1 (B) T F2 T controller valve process Exit stream setpoint (C) F3 F T T F2 controller valve process Exit stream setpoint F3 F2 (D) T T F1 controller valve process Exit stream setpoint 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 F, 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