Which statement regarding zero-film bearings is true?

Zero-film bearings are designed to operate without the need for traditional lubrication, which is why the statement describing them as lubrication-free is accurate. These bearings utilize advanced materials and technologies that allow for smooth operation without the introduction of lubricants, significantly reducing maintenance requirements and the risk of lubricant-related issues, such as contamination and degradation.

This characteristic makes zero-film bearings particularly advantageous in environments where lubrication is impractical or where the presence of oil or grease could cause contamination. The other options involve factors that are not inherent to the design or function of zero-film bearings. For instance, while they may be initially more expensive to manufacture due to advanced materials, this variability does not define their operation. Additionally, unlike traditional bearings that rely on lubrication for wear resistance, zero-film bearings are specifically engineered to manage wear effectively without the need for constant lubrication, resulting in a different wear profile compared to lubricated bearings.