What is the boiling point of cryogenic liquid?

The boiling point of cryogenic liquids is typically very low, often well below freezing temperatures, which is characteristic of substances that exist in liquid form at extremely low temperatures. Cryogenic liquids are those that are kept at temperatures around or below -238°F (-150°C), which is the point at which certain gases become liquefied.

C is the best choice because it specifies -243°F or lower, which appropriately describes the boiling points of many cryogenic liquids, such as liquid helium, with an actual boiling point of -452°F (-269°C). This option aligns with the definition of cryogenic temperatures, as they generally fall below -238°F for most common cryogenic liquids used in various applications, including technology and medical uses.

The other options do not accurately reflect the characteristics of cryogenic liquids. For instance, -100°F and -173°F are higher than the typical boiling point range for cryogenic substances, making them unsuitable choices. 0°F is also far too high, as it is above the freezing point of water and does not pertain to the cryogenic domain. Therefore, selecting -243°F or lower is a clear affirmation of the properties of cryogenic liquids.