Which of the following lists types of pressure sensing devices?

• A. A pressure gauge, manometer, and diaphragm
• B. A helical sensor, bourdon tube and bellows sensor
• C. Piezoelectric, capacitive, and optical sensor
• D. Hydrophone, accelerometer, and thermistor

Answer: (B)

The main idea is recognizing the actual mechanical elements that respond directly to pressure and translate it into a readable signal. Classic pressure-sensing devices are the components that physically move or flex in response to pressure: Bourdon tubes (including helical forms), bellows, and diaphragms. These elements form the core of traditional gauges and provide the mechanical basis for sensing pressure. The option that lists a helical sensor, a Bourdon tube, and a bellows sensor is the best fit because it names three genuine pressure-sensing elements. Other choices mix instrument-level devices (like a pressure gauge or manometer) with sensing elements, or bring in non-pressure-related sensors (like accelerometers or thermistors) or non-mechanical sensing technologies, which don’t fit as the primary pressure-sensing devices used in many water distribution contexts.