Birmingham is probably the most thoroughly segregated city in the United States.
Its ugly record of brutality is widely known.
Negroes have experienced grossly unjust treatment in the courts.
There have been more unsolved bombings of Negro homes and churches in Birmingham than in any other city in the nation
The answer is B, movie. "Action" is used as an adjective here, so it cannot be an object when there is no noun present. "Saw" is a verb. "I" is the subject, so the only remaining option is B, movie. The question to easily determine what the object is would be "What did you see?" And the answer would be "A movie".