G3B07

What does LUF stand for?

1. AThe Lowest Usable Frequency for communications between two specific points
2. BThe Lowest Usable Frequency for communications to any point outside a 100-mile radius
3. CThe Lowest Usable Frequency during a 24-hour period
4. DThe Lowest Usable Frequency during the past 60 minutes

Pick an answer to check it.