Which of the following systems is most likely to be subject to fading or static interference?

Correct Answer: Option A — HF SITOR

HF SITOR (Simplex Teletype Over Radio) relies on ionospheric propagation, which is highly susceptible to atmospheric noise, fading, and interference. Unlike satellite systems or VHF line-of-sight transmissions, HF signals fluctuate significantly based on solar activity and time of day, impacting the reliability of data transmission over long distances.