The Answer is B. I hope you get the test right :P!
In order to be able to answer this, we'd need to know what book it is you're reading, as well as the answer choices as the question asks "which of the following best" meaning that they want you to choose the best answer from the choices they’re giving you.
Answer: A) The writer could make the tone more academic.
Explanation: The tone of a text or sentence is the author's or speaker's attitude towards the audience, the subject or even the characters of the text. There are many different kinds of tones, like: positive, negative, objective, sad, angry, etc. From the given options, the one that represents how the excerpt could be best improved, is the corresponding to option A: A. The writer could make the tone more academic, by avoiding expressions like "totally important," "tons," and "it's obvious."
you would use a comma after.
example:
dear Mrs.Smith,
I was pleased to meet you.
sincerly, NK
