Which technology will carry a signal the greatest distance without a repeater?

Single-mode fiber-optic technology is designed to carry signals over long distances with minimal signal loss. This is due to its small core diameter, which allows light to travel straight down the fiber without bouncing off the walls. As a result, single-mode fiber is optimized for long-distance communication, typically ranging from several kilometers to tens of kilometers without the need for repeaters.

In contrast, multi-mode fiber has a larger core that allows multiple light modes to propagate, but this leads to modal dispersion, limiting its effective distance to a few hundred meters in most applications. Coaxial cable can transmit signals over relatively long distances, but it is still significantly less than what single-mode fiber can achieve, especially in high-frequency data transmission scenarios. While fiber-optic technology encompasses both single-mode and multi-mode options, single-mode specifically excels in long-distance applications.

Thus, single-mode fiber-optic technology is the best option for transmitting signals the greatest distance without requiring repeaters, making it the correct choice for this question.