Remember, your job in reading the passage is to find 1-3 sentences that you count as the Main Point, and to categorize the passage's purpose (which is almost always just picking from one or more of those 8 or so common RC passage purposes).
When you're doing Main Point / Purpose questions, those 1-3 sentences are your "Proof Window".
And you're looking for an answer choice that aligns with what you thought was the Purpose of the passage
Are you performing those two steps?
Every time you read a passage, your goal on the first read is PMS:
Purpose - (Clarify misconception? Problem/Solution? Old/New? Illustrate by Example? Highlight a Distinction/Deficiency? Defend from Criticism? Present a Debate?)
Main Point - Pick 1 to 3 sentences that to you best encapsulate the main point
Structure - You should be able to describe the function/content of each paragraph in 5-10 words, in relation to the passage's overall purpose and main point
So if you read the passage and correctly categorized it as "Illustrate by means of example" with lines 10-12 and 17-20 as your two Main Point sentences, you're better set up to like (A).
If you categorized the Purpose / Main Point sentences differently, then your job in reviewing the passage is to "read it again the way you WISH you had" in order to practice what you would have needed to see/think in order to align your Purpose / Main Point assessment with LSAT's.
If you just read the passage but never articulated to yourself what the author's Purpose or Main Point sentences were, then you're not practicing RC right.

I think you had good instincts that Alaska is enough of a "main character" in this passage that it should be in our Main Point answer, so your rationale for (B) as being too broad makes sense.
The other four answers all bring up the main topic character of Alaska / Alaska's sense of 'tradition'.