question: Who 's lack of concern helped the Mongols jump at a chance to reclaim their old vassal of Tibet ?
answer: the Ming court
turker_answer: The Ming court 's lack of concern helped the Mongols jump at a chance to reclaim their old vassal of Tibet .
rule-based: Lack of concern 's helped the Ming court the Mongols jump at a chance to reclaim their old vassal of Tibet .