Explanation:
Plot is related to mystery because plot is basically a plan, and you do not know what the plan is if it is carried out by another person.
Answer:
The State of the Union speech before Congress was largely about the national security of the United States and the threat to other democracies from world war that was being waged across the continents in the eastern hemisphere. ... He outlined the U.S. role in helping allies already engaged in warfare.
The answer is C. Appear is a verb and singular verbs normally end in -s. Also the sentence is talking about the conductor, not the pictures.
