The writer of the excerpt can best improve his or her grammar and mechanics by adding missing commas, as stated in option A and explained below.
<h3>Where should commas be added?</h3>
The excerpt is well written, and no sentence fragments are present, which means all sentence are complete. However, there are a couple of places where the use of commas is necessary.
First, we need to add a comma after the word "Europe" in the sentence "While some Vikings raided villages along the coast of northern Europe others traded furs for money." The reason for that is the fact that the sentence begins with a subordinate clause. A comma should be placed after that clause ends.
The same happens in the sentence "Though the Vikings gained a reputation as brutal savages they also created a body of literature celebrating their proud history." A comma should be placed after "savages" to show the end of the subordinate clause.
With the information above in mind, we can select option A as the correct answer.
Learn more about commas here:
brainly.com/question/2818981
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