About Ezra Pound, which of the following statement is true?

A. He made a reputation for himself as a member of the literary avant-garde(先锋派）when he settled in London.
B. He is widely considered one of the most influential poets of the 20th century and contributed to important literary movements such as Imagism.
C. Another important fact about Pound's literary activity was his tireless promotion of other writers and artists such as James Joyce and T.Eliot.
D. As an admirer and supporter of Mussolini, Pound was arrested at the end of World War II by US for his treasonous commentaries in Italy.