A is technically correct because it doesn't exist. What, does it remove "ar" from your future feed water? I hope that it isn't spelled that way on the tests.
Engine
General Subjects: In accordance with 46 CFR 61, which of the following pressure vessels listed on...
Discussing this exam question.
to comment above. A DFT does exist. Used on boiler feedwater to remove dissolved O2 from the water.