Answer:
The correct answer is: A. The mandate that high school seniors at Central High volunteer for a public service project is a welcome change to the high school graduation requirement.
Step-by-step explanation:
This is the appropriate way to start your conclusion paragraph, as firstly you have to get the main idea of your first paragraph of you essay, in this case, according to the lines provided, this answer is more suitable for this reason. The second option could be suitable for your final lines of your conclusion and the rest of options could also be used somewhere, as all of them provide good information which you probably able to use.