Question: who emerged as the head of the nationalist party and ruler of china by the late 1920s
[{'answer': 'Chiang Kai - shek', 'provenance': [{'wikipedia_id': '19780839', 'title': 'History of the Kuomintang', 'start_paragraph_id': 66, 'start_character': 551, 'end_paragraph_id': 66, 'end_character': 570, 'bleu_score': 1.0, 'section': 'Section::::Ideology in Mainland China (1920s–1950s).:Soviet style military.\n'}]}, {'provenance': [{'wikipedia_id': '19780839', 'title': 'History of the Kuomintang', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 755, 'bleu_score': 0.844921440169889, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1911749064439741722}, 'section': 'Section::::Abstract.'}]}]