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.
China apparently doesn't want N. Korea to have a nuclear capability.
I read up a bit about the Korean war this morning. Prior to 1945, Korea was ruled by Japan. Then it was split in two by Russia and America. Apparently North Korea attempted to unify Korea by force in 1950, with China and Russia's backing. But UN troops, mainly American, helped defend South Korea. But it seems there was never any signed treaty between the north and the south after that.
The split between the two countries is a by-product of the Cold War, and the difference between the them is one is communist, one is not. With Communism in decline, it seems any unified Korea would be more likely to be non-communist.
Maybe for now the best outcome would be for North Korea to recognize South Korea and work towards a more peaceful relationship. As for nuclear capability, I'm not sure why China wouldn't want them to have it. Perhaps it would enable North Korea to maintain its independence?
