Multimode Fiber vs Copper: Crosstalk and Throughput

The boundary: resistance versus immunity The decisive distinction here is between media that merely reduce crosstalk and a medium that never carries an electrical signal that could couple. Shielded twisted pair (A) and Cat 6 Ethernet (D) use copper conductors; their twists and shielding lower crosstalk and EMI, but the signal is still electrical, so the impairment is mitigated, not removed. A community explanation of option C puts it directly: optical fiber sends light through glass or plastic, making it “completely immune to electromagnetic interference (EMI) and crosstalk.” That is the side of the boundary this scenario occupies.

Why the other constraints do not rescue copper or wireless The question removes distance and cost as limiting factors. That matters because copper’s usual advantages are cost and easy termination, while fiber’s usual drawback is cost and handling. With those disqualified, A and D only offer reduced crosstalk and lower theoretical ceilings than fiber. Option B, 802.11ax, is a wireless standard, not a transmission medium in the same cabling sense; it is also exposed to RF interference and shared-air contention, so it cannot provide the “most protection from crosstalk.”

Fastest theoretical throughput Multimode fiber (C) supports very high aggregate rates over its intended distances, and the wording asks for theoretical throughput rather than a guaranteed deployed rate. Cat 6 is typically associated with 10 GbE at limited distance, STP is lower, and 802.11ax’s theoretical rates are shared and radio-dependent. Once cost and distance are declared irrelevant, the fiber’s optical bandwidth wins.

Verdict C is the only option that satisfies both remaining requirements: immunity, not just resistance, to crosstalk, and the highest theoretical throughput among the listed media.