Of course North Koreans would welcome literal carrots - it would make a nice dietary change from the frequent bouts of starvation Kim forces them to endure. The diplomatic carrot for NK however is also pretty obvious and comes in the form of a thriving economy and integration with the global system of trade and all of the attendant benefits that would accrue to NK's citizenry were this to occur. The regime however has no interest in mind but its own survival and continued aggrandisement so in this sense the carrot must be allowing them to continue with their hermit ways, oppressing the the NK people but not threatening the world beyond their borders. So far "carrots" are consumed by the NK regime with no sense of corresponding obligation or sense that this will encourage them to alter their course.