An exhaust gas detection system for an engine is required. When the CO and NOx concentrations are both within the acceptable limits a green light should be on. If the CO concentration is below the acceptable limit but the NOx concentration is too high, an orange light should be on. If both the CO concentration and the NOx concentration are too high a blinking red light must be on. CO is dangerous, so if the CO concentration exceeds its acceptable value a warning sound should go off immediately. Design the logic circuit for this system.