It depends on the type of map you show. My guess is the second one.
Explanation:
The last choice is clearly wrong as New York and Vermont are both in the US, so no national boundaries there. Also, national boundaries are the highest level boundaries there are, so I presume that it would be thick. My guess would be the second one. However, you copied this question and there seems to be an 'O' on the second choice. I think you already know the answer.
