I don't think there are only two options. Another one is that N. K. keeps testing bombs, and nobody does anything, well, barring sanctions. Everybody is worried about the retaliation, not against the US, but S. Korea, as no doubt N.K. has a ton of weaponry aimed across the border. The first bomb to fall on N.K. may provoke this, all along the border and aimed at Seoul also.
This has unforeseen consequences - another Korean war, China intervening, because they don't want US bases against their frontier, millions of refugees, and so on. It's true that Trump is crazy, but his generals will be warning him.