An Ultrasonic Nebulizer Is Not Putting Out Any Mist

An ultrasonic nebulizer is not putting out any mist. After confirming (1) good electrical power supply (cord, plug, and circuit breakers are in good working order) , (2) carrier gas is actually flowing through the device, and (3) the output control is set at maximum, what should you do?

A) Take the unit out of service and send it to engineering for repair.
B) Inspect the couplant chamber to confirm cleanliness and fill level.
C) Disassemble the radiofrequency generator and test for electrical leakage.
D) Hook it up the chamber inlet to a flowmeter set at 10 L/min or higher.