I was always taught to cite mine like C. I am so sorry if it's not right it's just the way I was taught I would figure it would be the same.
Trees help purify our air. When the air is to contaminated trees take in all that contamination so we can breathe better.
Answer:
C. Children know much that grown-ups have long forgotten
You wouldn't use the hyphen in this case, so the answer would be B one tenth :)