Which North Korean actions in the 2000s resulted in condemnation by other East Asian countries?

The action by North Korea in the 2000s that resulted in condemnation by other East Asian countries was primarily their development of a nuclear weapons program. This program led to widespread concern and condemnation from countries in the region, including South Korea, Japan, and China, as well as from the international community. The other options listed—attempts to trade with the U.S., an invasion attempt of China, and a peace treaty with Japan—did not occur and would not have evoked similar condemnation. North Korea's nuclear ambitions were a central issue in East Asian security discussions during that time.