Where Should You Place the Thermistor Probe for a Servo-Controlled

Where should you place the thermistor probe for a servo-controlled heated humidifier being used on a patient receiving mechanical ventilation?

A) in the expiratory limb of the circuit, near but not at the "wye"
B) in the inspiratory limb of the circuit, as close to the "wye" as possible
C) in the expiratory limb of the circuit, as close to the "wye" as possible
D) in the inspiratory limb of the circuit, near but not at the "wye"