Be becuase infinitives always have “to” in them
What I know of that it Scrooge is visited as the bell tolls at one o'clock by the first of three ghosts, as promised by Marley's ghost: the Ghost of Christmas Past. The apparition is a curious figure' that both an old man and a child appear to be.
Because is the correct answer. The word because is connecting the two statements together and explaining how they finished their work.
As long as you clearly state the sources and resources of information it should be fine.
Answer:
topic sentences state the main idea.
