The correct answer would be letter C.
Yes, because even though other trees produce more oxygen, the small trees will still produce some oxygen. On top of this there are more small trees than big trees, so even though they make less oxygen, in whole they end up making more when added together!
Always melt chocolate slowly, at a low temperature. The melting point of chocolate is between 86 degrees F. (30 degrees C.) and 90 degrees F.