It is A. Documents that were written in the past. It is in the past therefore part of history... (had to add some extra words to give the answer lol)
B. The use of words such as "planetary" and "potential" helps establish a formal style.
<span><span>"he heard the slap of the window curtains
against the wall and the sound of paper fluttering from his desk,
and he had to push to close the door." quoted from the book</span></span>
D) They are built by the deposition of sand by wind
