Which of the following statements are correct?

what are the others?

the answer would be a i think?

a. poison gas was sprayed over battlefields by airplanes to weaken enemy positions before major attacks.

populist movement, in u.s. history, politically oriented coalition of agrarian reformers in the middle west and south that advocated a wide range of economic and political legislation in the late 19th century. thus in 1892 their leaders organized the populist, or people's, party, and the farmers' alliances melted away.