PT56.S2.Q24 - over 40,000 lead seals

apublicdisplay

Link to question and explanation:

https://7sage.com/lsat_explanations/lsat-56-section-2-question-24/

I watched J.Y.s explanation and he says that we're presuming the documents were in fact opened. But, is it really a presumption when the author explicitly says "WHEN the document was opened"? The author says when (in other words "if") the document is opened, then Y results. And then with (A), we're just confirming the sufficient condition, saying yes it was opened. Is that considered an assumption?

runiggyrun

The author is saying "when (if) the document was opened, the seal was reused", therefore there must have been a lot more seals originally than what we still have.
But what if none of the documents were opened? Only 40,000 seals were affixed, and they were all on super important stuff that was never opened. The "if" in the author's premise never gets triggered, so the conclusion is false.
Answer A makes sure that we trigger the sufficient condition. If we negate A (most of the seals were affixed to documents that were never opened) then it doesn't matter what happens if/when they are opened, because they weren't opened