In Question 5, is it theoretically plausible that "this is not a sustainable, long term solution" is merely context?

Grammatical error detected: A group of Britisher researchers BELIEVES — a group is singular.

Question 4: How are we sure that there's a relationship between the three sentences, thereby proving existence of argument? Linguistically? How can we reasonably assume that "he" is "the kid" or that "He" from premise 1 is the same "He" from premise 3?