Which of the following best describes 'Optical fibres'?

Optical fibres are specifically designed to transmit light signals over distances, utilizing total internal reflection to guide the light along the fibre. This technology primarily involves the use of glass or plastic materials that have optical properties suitable for light transmission. The core of the fibre allows light to pass through with minimal loss, making it an efficient medium for communication, particularly in telecommunications and networking.

The other options do not accurately represent the function or nature of optical fibres. For instance, metal wires are used for conducting electric current, which is fundamentally different from how optical fibres operate. Plastic tubes may serve functions related to sound transmission, but they do not involve light transmission like optical fibres do. Additionally, while coated wires can be involved in data transfer via electrical signals, this again does not align with the light transmission aspect that defines optical fibres. Thus, option B accurately encapsulates the essential characteristics and purpose of optical fibres.