Question: What German ace-of-aces was shot down by Cedric Bassett Popkin during World War 1?
Sentence (from "Cedric Popkin"): Cedric Bassett Popkin (Born 20 June 1890, died 26 January 1968) is considered the person most likely to have killed German ace Manfred von Richthofen — also known as the "Red Baron" — on 21 April 1918.
Relevant evidence: Yes