a) Bourdon tube pressure gauges
b) Barometric sensor
c) Piezoelectric pressure sensor
d) Piezoresistive pressure sensor

Answer: d
Explanation: Piezoresistive pressure sensoruses the change in electric resistance of a material when stretched to measure the pressure. Due to the simple design and robustness, this instrument is used for wide range of applications. These are used for gauge, absolute and relative pressure measurement in both high and low pressure applications.