How is squelch adjusted so that a weak FM signal can be heard?

To hear a weak FM signal, the squelch must be adjusted to a level that allows the faint audio to come through. Setting the squelch threshold so that the receiver output audio is continuously on ensures that even weak signals that wouldn’t normally break through the squelch noise can be heard. This is particularly important in weak signal conditions where the noise floor can mask the audio of the faint transmissions.

When the squelch is set too high, only stronger signals will be audible, which means that if you're trying to listen to weak transmissions, they will likely be suppressed. By keeping the squelch open continuously, the user can listen to all incoming signals, allowing for the detection of low-power or distant transmissions that might otherwise be lost.

The other options either suggest incorrect adjustments or functions that do not specifically address the need to lower the squelch threshold to hear weak signals.