Question: Which screenplay by Kenneth Ross  was directed by Fred Zinnemann?
Sentence (from "The Day of the Jackal (film)"): Based on the 1971 novel "The Day of the Jackal" by Frederick Forsyth, the film is about a professional assassin known only as the "Jackal" who is hired to assassinate French president Charles de Gaulle in the summer of 1963.
Relevant evidence: No