The correct answer is C. Modernism in literature usually refers to the period between 1910 and 1930, with 1922 as its epicenter since Joyce's Ulysses and T.S. Eliot's The Waste Land came out that year. Modernism therefore predates the Great Depression.
All the other topics were covered by the modernists. Eliot dealt with the alienation of the individual and the crowded city life in The Waste Land and Hart Crane lamented the ever-greater materialism in American society in The Bridge, while the brutality WWI was the subject of many poets from all the participant countries. Pound dealt (although eliptically) with the war in Cathay, his book of versions of Chinese poems, and more explicitly in Gaudier-Brzeska: A Memoir.
