The answer is D.
"Keep", "factor", and "calculate" are all verbs in the list of things the new system allows teachers to do. The other sentences are inconsistent with their list of verbs/adjectives/nouns. Thus, option D is the only one that is grammatically correct.
I am not too good at explaining, so let me know if you are still confused.
Hope this helps! :)
Answer:
show or explain to (someone) how to do something.
Explanation:
He asked for peace and trust in book 13
The part of speech is conjunction.
I know this is late but the answer was The fire ate through the forest because in that sentence it was like the fire was living
