I would say B: Paragraph 3
This would be a good place to place a counterclaim where your claim is "Immigrant contribute to the US economy" so you can show your unbiased and state "Yeah they effect our economy but sometimes in a bad way as they can drain us of our resources and negatively affect it"
Simply just to tell them to stop or force them off it
The correct answer is C. i took the test so thats the right answer
It is necessary because if you don't have a confirmed opinion with textual evidence to back it up you wont have a good argument.