There's a missing option: unilateral sanctions. North Korea was basically funding itself by producing expert forgeries of U.S. currency. The U.S. has cranked down hard on that, for obvious reasons. In effect, the U.S. was unwillingly giving significant financial support to North Korea, and now it's not. That's arguably one of the reasons that North Korea got serious about bomb-making.

Now, the big question remains how and what China will do. Unlike the U.S., they do talk to the North Koreans, and may now be willing to threaten them.