Which of the following cable types can be used to decrease susceptibility to electronic eavesdropping?

Fiber optic cable uses light to transmit data through glass or plastic strands, producing no electromagnetic emissions. Because there is no electrical signal to intercept, passive eavesdropping methods such as inductive taps do not work. Physical tapping of fiber is also difficult and detectable due to signal loss.

Fast Ethernet is a speed specification that typically runs over copper twisted-pair cabling, which does emit electromagnetic signals susceptible to interception.

Coaxial cable carries electrical signals and can be tapped with an inductive coupler without breaking the circuit, making it vulnerable to eavesdropping.

Thicknet (10Base5) is an older coaxial cable standard that uses electrical signaling and is equally susceptible to electromagnetic interception as other copper media.