What type of primary element for a pressure transmitter would be most suitable for measuring oil-fired boiler furnace and forced-draft pressures?

Correct Answer: Option B — Diaphragm pressure sensor

Diaphragm sensors are highly sensitive to the very low pressure differentials found in boiler furnaces and forced-draft systems. Their design allows for accurate measurement of these low-pressure ranges, where heavier sensors like Bourdon tubes would lack the necessary sensitivity to detect small changes in pressure.