I think your answer is B, in the 1920s the American economy began to contract and the depression lasted about a year
Oklahoma's economic history is divided into four periods. The first period covers the nineteenth century, encompassing settlement by American Indians of the Southeast followed by new arrangements facilitating private land ownership. The second extends from 1900 to the onset of the Great Depression in 1930. The third ends in 1973 with the first of the major oil shocks. The fourth comprises the energy boom and bust of the late twentieth century, along with contemporary conditions.
The century from 1800 to 1900 encompassed the time of Indian and white settlement. During the nineteenth century Oklahoma was characterized by very high ratios of land to labor and capital, by almost total dominance of primary (natural resource based) production, and by unique institutional and cultural features, of which the effects of some remain important in today's economy. The initial settlement by the Five Civilized Tribes in the 1820s, 1830s, and 1840s in what is now Oklahoma (at that time Indian Territory) did not reflect free-market labor migration in response to income differentials. Added to the coercion of removal was the fact that the Five Tribes had adopted the institution of slavery in their former southern setting. Slave-owning Indians brought with them an additional labor supply.
The correct answer is that international volunteers fought on the Republican side in the Spanish Civil War.
The Republican side was formed around the Government, formed by the Popular Front, which in turn was composed of a coalition of Republican parties - Republican Left and Republican Union - with the Spanish Socialist Workers Party, which had joined the Marxists - Leninists of the Communist Party of Spain and the POUM, the Syndicalist Party of anarchist origin and in Catalonia the left nationalists led by Esquerra Republicana de Catalunya. It was supported by the labor movement and the UGT and CNT unions, which also pursued the social revolution. The Basque Nationalist Party had also opted for the republican side, when the republican courts were about to approve the Statute of Autonomy for the Basque Country.
Although it received hardly any external support from the allied powers of the Second World War, due to the International Non-Intervention Committee, the support of the USSR, which together with Mexico together with France and Poland at the beginning of the contest, stand out; they contributed large quantities of military equipment and advisors, notoriously also the support of what were called the International Brigades.
