A bourdon tube must be fabricated from a material that has elastic properties so that it -----

A bourdon tube must be fabricated from a material that has elastic properties so that it can deform under pressure. The primary function of a bourdon tube is to measure pressure, and its operation relies on the ability of the tube to change shape in response to an applied pressure. When pressure is applied inside the tube, it causes the tube to expand or bend, which in turn indicates the pressure on a connected gauge.

The elastic behavior of the material is crucial because it allows for the tube to return to its original shape once the pressure is removed. If the material did not have suitable elastic properties, it might either fail to respond accurately to pressure changes or could permanently deform, leading to unreliable readings.

The other options highlight different material characteristics that may be beneficial in certain contexts, but they do not directly address the primary functional requirement of the bourdon tube as a pressure sensor. The ability to deform under pressure is paramount for accurate pressure measurement and functionality of the device.