A. The author included this to show that the only part of wood that is useful to people is its carbon.


B.
The author included this information to explain how the process of making charcoal is so complicated that many people no longer use it.


C.
The author included this paragraph to sound more knowledgeable and establish this text as a reliable source of information about charcoal.


D.
The author included this section of text to provide a serious element to the text because the rest of the text has a humorous, lighthearted tone.