Hi Sjd207,
Thank you for the question.
You are not alone. Method of reasoning questions often give students difficulty.
The stimulus presents us a dialogue , but then the question stem tells us we just have to focus on Rossi's argument. This means we can safely ignore Smith for this question.
First we try and paraphrase Rossi's argument. He makes a statement about representation in government and then applies it to a group of people(children)
Now we can look at the answer choices and determine which one best fits.
(A) the statement could be considered a principle so we keep this.
(B)There is no opponent mentioned. So this is out.
(C)There is no consequences mentioned. We can eliminate this one
(D)No substitution of description for rational, We strike this.
(E)There is no term used in two different senses, so this is out.
By focusing on Rossi and paraphrasing the argument we can go thought our answer choices and come to the correct answer fairly quickly.
I hope this helps.
Bob