When designing a backbone distribution system, you are asked to include a combination of media types. Your choice of media types include:

Limiting media to copper and fiber only incorrectly excludes wireless, which is a recognized backbone medium under ANSI/TIA-568 and increasingly common in modern deployments.

Excluding copper is incorrect because twisted-pair copper remains a valid and commonly used backbone medium, particularly for shorter distances within a building.

Coaxial cable is not a recognized backbone media type in current ANSI/TIA-568 structured cabling standards, making this combination non-compliant.

This combination pairs two non-standard or excluded media types - coaxial is not recognized in TIA-568 backbone specifications, and excluding fiber and copper eliminates the two most widely deployed backbone media.

ANSI/TIA-568 explicitly recognizes copper balanced twisted-pair, optical fiber, and wireless as all valid backbone media types, and allows them to be used in any combination within a single installation. This flexibility enables designers to select the optimal medium for each backbone segment - for example, fiber for long inter-building runs and copper for shorter intra-floor connections - ensuring the system meets both performance requirements and budget constraints.