A student asked me about this question earlier, and in typing out a relatively comprehensive response it occurred to me that my reply might prove useful as a complement to Jeremy's excellent explanation above. So here goes!
The mechanics of this Justify question are actually fairly simple, or at least common enough that once you’ve seen this a few times it becomes easy enough to spot and attack.
Essentially what you get in this argument is a somewhat generic introduction—there’s a correlation between popular appeal and sales/money (which is a given, and the sort of thing the LSAT would consider a valid assumption based on common knowledge of economics)—followed by a pair of conditional statements that contain the conclusion:
1. Premise: Serious novelist
Care about literary style
2. Conclusion: Serious novelist
Not motivated primarily by desire to make money
Note: #2 exhibits the form “No one who...,” which is something that always translates as “Members of the group in question lack some quality/characteristic.” So, “No As are Bs,” is just A
Not B, etc. That’s why I showed it the way I did, if anyone's unsure
So, we know our conclusion’s starting point—"Serious novelist”—gets us to “Care about literary style” because the premise told us that, but the author goes further and tries to get from that starting point (Serious novelist) to a new idea, “Not motivated primarily by desire to make money.” To connect those terms we just need the end of the premise—“Care about literary style”—to take us to the conclusion’s destination!
It would be like if I said:
Prem: A
B
Conclusion: Thus, A
C
How do I get that conclusion from that premise? Add another premise: B
C. That would make a chain:
Prem: A
B
New Prem (answer choice): B
C
Conclusion (proven): A
B
C , thus A
C
That’s all that happens in this argument with the addition of answer choice (B), which merely a new connection between the premise’s endpoint and the conclusion:
Prem: Serious novelist
Care about literary style
New Prem (answer choice B): Care about literary style
Not motivated primarily by desire to make money
Conclusion (proven): Serious novelist
Not motivated primarily by desire to make money
As for the arrow or connection direction idea, the key thing to keep in mind is that you need to move
from the premise
to the conclusion’s end point, thus
from “Care about literary style”
to “Not motivated primarily by desire to make money,” and NEVER the other way around! Reversing that flow is a favorite trap, particularly in harder questions (I don’t see an answer that does it here but it’s worth watching out for). In short: anything that takes you from the conclusion and sends you elsewhere is wrong!
Again, they do this all the time, albeit sometimes directly as here, and other times with contrapositives, like “Motivated primarily by desire to make money
Not care about literary style.” That’s a bit trickier, but the principle is the same.
Hope that helps!