What is one of the key characteristics of fiber-optic cables?

Fiber-optic cables are characterized by their ability to transmit data at very high speeds. This is due to the use of light signals transmitted through glass or plastic fibers, which allow for faster data transfer rates compared to traditional copper cables. The high-speed transmission capability of fiber optics makes it suitable for applications requiring large amounts of data to be sent over long distances with minimal loss and interference. This is why the choice highlighting high-speed transmission is the correct answer.

In contrast, options that mention copper strands or coaxial connections refer to different types of cabling that do not utilize light for data transmission and are typically slower. The mention of low-speed transmission does not accurately reflect the capabilities of fiber-optic technology, which stands out precisely for its high-speed performance.