Answer: D is right. But there are also many other reasons.
Explanation: League of Nations was formed by Allied powers (from the WW I) so consequently it was viewed as "League of Victors". Moreover USA did not join, may other states did not join and later on League of Nations was unable the prevent outbreak of WW II.
Flying Tigers. The 1st American Volunteer Group (AVG) of the Chinese Air Force in 1941–1942, nicknamed the Flying Tigers, was composed of pilots from the United States Army Air Corps (USAAC), Navy (USN), and Marine Corps (USMC), recruited under presidential authority and commanded by Claire Lee Chennault.
