Final answer:
Labyrinth seals are primarily used with natural gas compressors, as they effectively reduce gas leakage in high-pressure applications by providing a complex path that increases resistance and lowers pressure differences.
Step-by-step explanation:
Labyrinth seals are most often used with C) Natural gas compressors. These complex seals are designed to reduce leakage of the compressed gas by creating a complicated path for the gas to follow, which consists of a series of ridges and cavities. This arrangement effectively decreases the flow of gas across the seal by increasing the resistance and reducing the pressure differences that drive the leakage. Labyrinth seals are particularly beneficial in high-pressure applications where minimizing gas loss and ensuring efficiency are critical, such as in natural gas compressors where gas is often compressed to high pressures for transportation and storage.