Which of the following media types is most immune to RF (Radio Frequency)eavesdropping?

A.
Coaxial cable

B.
Fiber optic cable

C.
Twisted pair wire

D.
Unbounded

Explanation:
Fiber, as a media, is relatively secure because it cannot be easily tapped. It is the strongest to defeat against EMI and RFI in my opinion.
Reference: Security + (SYBEX) page 147