Consider the following statements regarding the propagation of radio waves in the Earth's atmosphere: 1. Medium and shortwave radio signals can travel long distances around the globe because they are reflected back to Earth by the ionosphere. 2. Very High Frequency (VHF) and Ultra High Frequency (UHF) signals penetrate the ionosphere and are used for line-of-sight or satellite communication. 3. The ionosphere's ability to reflect radio waves is due to the presence of free electrons and ions created by solar radiation. Which of the statements given above are correct?

Options:

• A: 1 and 2 only
• B: 1, 2 and 3
• C: 2 and 3 only
• D: 1 and 3 only

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