The answer is c .. (that the bottom)
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. The shark-faced nose art of the Flying Tigers remains among the most recognizable image of any individual combat aircraft or combat unit of World War II.
The group consisted of three fighter squadrons of around 30 aircraft each. It trained in Burma before the American entry into World War II with the mission of defending China against Japanese forces. The group of volunteers were officially members of the Chinese Air Force. The members of the group had contracts with salaries ranging from $250 a month for a mechanic to $750 for a squadron commander, roughly three times what they had been making in the U.S. forces. While it accepted some civilian volunteers for its headquarters and ground crew, the AVG recruited most of its staff from the U.S. military.
I wanna say the answer is A I don't really think the other choices would be considered "strengthening activities "
