What defines a cryogenic device?

Cryogenic devices are specialized systems that operate at extremely low temperatures, often defined as below -150°C (-238°F). The correct response focuses on a system that is specifically designed for measuring and delivering cryogenic liquids while maintaining them in a liquid state. This is crucial because liquid cryogens require careful handling to ensure they remain below their boiling points under pressure or at atmospheric conditions.

Such systems may involve intricate engineering solutions to prevent phase changes, like vaporization, which could occur if the substance isn't adequately contained or managed. This functionality is essential in various applications, including scientific research, medical technologies, and aerospace, where precise temperatures are necessary.

The other options highlight aspects related to measurement or transport but do not encompass the essential element of maintaining the cryogenic state of liquid gases during delivery. Consequently, the focus on both measurement and retention of cryogenic liquids solidifies the definition of a cryogenic device as presented in the correct choice.