D. High school students should be required to do community service in order to graduate because it helps them build social awareness, take a greater interest in their communities, and gain necessary job skills.
Explanation:
Syntax coordination is the alignment of two syntactic units, two sentences, or two terms with the use of conjunctions or punctuation marks. This generates what is called parallel structures. These structures allow all ideas of the sentence to be on the same level of importance and usually occurs through the use of conjunctions such as "and", "or" and "so."
With this concept we can see that the right answer is the letter D.
