A fan is connected to a duct system and is moving 300 CFM of air. The velocity in the duct is 150 FPM. Which of the following duct sizes would be the correct duc size for this system?

A fan is connected to a duct system and is moving 300 CFM of air. The velocity in the duct is 150 FPM. Which of the following duct sizes would be the correct duc size for this system?