The most reliable method of checking or testing a low water fuel cutoff is to:
a. Blow the low water cutoff down through the water column until the burner cuts out.
b. Blow the float chamber down to see if the burner will cut out.
c. Lower the water in the boiler to the level where the burner should cut out.
d. Blow down the sight glass to see if the burner goes out.
e. Manually trip the mercury switches to shut off the burner.
Answer: C