G9A07:What must be done to prevent standing waves on a feed line connected to an antenna?
Direct answer summary (2023-2027 NCVEC pool)
The official correct answer for G9A07 is The antenna feed point impedance must be matched to the characteristic impedance of the feed line.
The key fact is The antenna feed point impedance must be matched to the characteristic impedance of the feed line. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.