The key fact is Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.
The official correct answer for E4C13 is Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals.
The key fact is Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.