In the course of her researches, a historian recently found two docume

Here is what i thought when I read this question and options: I went down the list of options. I noticed that some of them are comparing the two actions - "arrest for peddling in 1739" and "Assertion that he has been peddling off and on for 20 years"

Here were my thoughts - "arrest for peddling" doesn't mean he was actually peddling at that time. Whether he was actually found guilty or was guilty, I don't know.
HIs assertion was that he has been peddling off and on for 20 years. In my mind, I thought that well, he could have said that before his arrest (he stopped but was later arrested because they found proof against him after a year), at the time of his arrest or years after his arrest (perhaps he was imprisoned only for 2 months which was his off period; later he was on again!)

(A) Schnitzler started peddling around 1719.
This is assuming that he made his assertion at the time of arrest. There is no reason to assume that. Not true.

(B) Schnitzler was arrested repeatedly for peddling.
The argument does not imply that anywhere.

(C) The undated document was written before 1765.
At first, I skipped over it. This is possible but if I assume that at the time of his arrest, he was actually guilty. "Before 1765" means just that - "sometime before 1765". So if he makes this assertion in 1750, it is still before 1765. Assuming he was peddling in 1739, he could have made this assertion at any time before 1739, during 1739 or 20 years after 1739 i.e. in 1759. All possible years in which he could have made his assertion would be before 1765. It is the same as saying that the document was written before 1900 or before 2005 etc.

So, I went to the next option keeping this in mind but not fully convinced with it.

(D) The arrest record was written after the undated document.
As we discussed before, there is no reason to assume "before", "during" or "after".

(E) The arrest record provides better evidence that Schnitzler peddled than does the undated document.
Not true. We cannot say which is better evidence. Perhaps his own assertion should be considered better. It is highly unlikely that he would want to malign his own reputation. But then, perhaps the official arrest with date is better. We cannot say. How do we define what is better evidence? This option is asking you to take a call - you cannot do that. You have to look for a conclusion of the argument only.

This leaves us with (C) only. Best of the lot.