There really aren’t, North Korea has thousands pieces of artillery aimed at Seoul.
Whether there are or are not...is not the point. The point is simply we do not let the enemy *know* we don’t think there are options.
But, certainly, there are options. If we felt we must move toward a military solution...we would clearly need to work with South Korea to evacuate Seoul. That in itself might be a step to convince China we are serious. and lead them to squash Kim once and for all.