Hi teddykim100!
Am I wrong in saying that B's "if" is not actually triggered in the stimulus?
Is this because this is a Justify question, that we don't need to follow the conditional logic precisely?
I'm not sure I understand the question about the "if" in (B) being triggered in the stimulus, but I can reiterate why that answer choice is correct. Since this is a justify question, we need something that is sufficient to allow the conclusion to be drawn. Here, the conclusion is that "one should not regret the missed opportunities of youth." Why does the author conclude this? The author explains that one should not regret this because those missed opportunities led to the relationships one now has, which the stimulus states that everyone cherishes.
There's a gap between the conclusion about regret and the following sentence about what everyone cherishes. Answer choice (B) bridges this gap. If one should not regret making a decision if it helped to bring about what one cherishes, then it follows that one should not regret the missed opportunities of youth, since these brought about what one cherishes. If (B) were added to the stimulus, it would thus be sufficient for the conclusion to follow from the premises.