Hi Lauren,
For this question, the "relevance" is related to the response of the author. So, we can think of the question stem this way: there is an objection to allowing people to make their own decision because they could decide anything. The author defends this by saying that if we allow the "designated decision makers" to make the decisions instead, they could also decide anything. Is the author's defense relevant?
Now, for answering the question, similar to any 2-part answer choice, don't focus on the relevant vs. irrelevant, but on the statement. See which statement might be true first.
Hope this helps!
Meaghan