I chose (C) for the following reasons:

- The hypothesis for which we have to find support is that the treatise was produced in 1148
- To produce a treatise, someone has to write it and the writing takes time
- If writing the treatise was very time-consuming (say it took several months to produce one page), even it the fourth author started to write in 1148, he couldn't have finished it

What's wrong with this logic?

Also, I still don't understand what's wrong with vannbj's logic?



Anyone?

Found the logic below in a different forum and I felt the explanation was great..

There seems to be a causal relationship involved...the argument says that there was a disruption that interfered with the copying of the Codex...then it proceeds to say that there was a letter from the 4th copyist about a plague in 1148(which happens to be the disruption) and this plague(disruption) caused the Codex to be produced that year.

Cause: Plague of 1148 (C)
Effect Delayed the Codex to be produced that year. (E)

C->E

Remember that in a causal relationship the author assumes that no other cause is responsible for the Effect. And he assures us that this cause is very much true(here he states that there was some significant disruption that caused the delay in produce - the plague of 1148).

Following this, we need to Strengthen the authors assumptions about his causal relationship by either:
1) showing C causes E
2) Eliminating other Causes
3) Eliminating reverse causality
4) Showing data used to make causality is accurate
5) if there is no cause then there is no effect.

Answer choice D properly demonstrates rule 2 "Eliminating other Causes"...if this was not the only plague then perhaps a later plague further delayed the Codex produce ...hope this helps...

(This question is particularly difficult because the causal relationship is difficult to spot, but you can try to do so by looking for Causal identifiers like "Since....<this>"..."therefore <this>")
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This is a very tricky question. I got the correct answer in <2 minutes using the process of elimination, but it was mostly a "feeling" that option D is the right answer. So, I spent a lot of time on trying to decipher it. Here are my thoughts. Hope it helps others get it, and I also hope someone will correct me if my thinking is wrong.

Conclusion: Codex Berinensis (hereby referred to as CB) was probably produced in 1148.
How did we reach this conclusion?
1. Guy 1 copied the first 80 pages --> disruption --> 10 pages by guy 2 --> disruption --> 10 pages by guy 3 --> disruption --> completed by guy 4.
2. Guy 4 also wrote a letter that mentions about a plague in 1148. It's tricky to know for sure if Guy 4 wrote this letter in the actual CB or just wrote the letter to someone. The first sentence "contains clues to when it was produced" is ambiguous in its meaning.

The final sentence can be summed up as: Because letter by Guy 4 mentions plague --> CB produced in 1148.
That's a huge jump. How does a letter written about a plague lead to the conclusion that the CB was produced in 1148?
Only if the plague played a role in producing the CB!

Now, this becomes easy. All we have to prove is that there was no other plague (other than the one that took place in 1148) that could have played a role in producing the CB.
In other words, what we're trying to support is that the CB was produced in 1148 and NOT BEFORE then. This is critical. I also fell into the trap of thinking: why can't the fourth guy have finished his work in 1180? But that's the wrong direction to think in.

I personally didn't buy into the fact that the plague was what caused the disruption for the first 3 guys in copying the CB. Maybe they moved, maybe they got another job, maybe they became disinterested in a repetitive and boring job. But it's not out of order to think that the plague caused the disruption. Who knows? All I have to prove is that the plague is 1148 played in role in producing the CB, and that it was no other plague. Option D does that.

Major Takeaways
- parsing out the truly unnecessary from the necessary. Once you understand what the argument is, and how it's made, the whole thing falls into place. Once I understood that the only thing I REALLY have to prove/support is that the plague of 1148 played a role in producing the CB, the rest became easy.
- I should have paid more attention to the last sentence and identified the jump in logic it was making. This took the longest time. Don't fight the jumps in logic with confusion and immediately jump to the answer choices.
- USE your confusion as the hole that you have to pour cement into.

Great question! Really haven't been challenged by a Strengthen question like this before.