Which of the following liquid level sensors would be most suitable for measuring the liquid level in a pressure vessel such a water-tube boiler steam drum?

Correct Answer: Option B — Differential pressure sensor

Differential pressure sensors are ideal for steam drums because they measure the head of water while compensating for the varying steam pressure above the liquid. This provides an accurate, stable level reading despite the high-pressure environment, which is critical for maintaining safe boiler water levels under 46 CFR Subchapter F.