What is one of the aspiring members of NATO?

The correct choice, Ukraine, is considered one of the aspiring members of NATO due to its strategic interest in joining the alliance to enhance its security and defense capabilities, especially in light of the ongoing conflict with Russia. Ukraine has expressed a strong desire to align itself with Western military standards and has been participating in collaborative frameworks with NATO, including joint exercises and reforms to meet NATO criteria.

On the other hand, Switzerland and Austria have a long-standing policy of neutrality and have chosen to stay out of military alliances like NATO, focusing on maintaining independence and neutrality in global conflicts. Japan, while a key partner of NATO and involved in various cooperative security arrangements, is not pursuing NATO membership. NATO is primarily a transatlantic alliance, and Japan's geographical location makes direct membership impractical. In summary, Ukraine's aspiration to join NATO is driven by its need for collective defense and security in a challenging geopolitical landscape.