What was the significance of the immigration acts of 1921 and 1924? :
a they limited immigration from mexico for the first time.
b they created a category of "special immigrants," which included relatives of u. s. citizens living abroad.
c they made immigration requirements qualitative, rather than quantitative.
d they set quotas on immigration from certain areas of europe, asia, and africa.
e they based annual quotas on a flat one-sixth of one percent of the national population in 1920.