Question: who is the singing voice of the chief in moana
[{'answer': 'Christopher Jackson', 'provenance': [{'wikipedia_id': '44164132', 'title': 'Moana (2016 film)', 'start_paragraph_id': 20, 'start_character': 12, 'end_paragraph_id': 20, 'end_character': 31, 'bleu_score': 1.0, 'section': 'Section::::Cast.\n'}]}, {'provenance': [{'wikipedia_id': '44164132', 'title': 'Moana (2016 film)', 'start_paragraph_id': 20, 'start_character': 0, 'end_paragraph_id': 20, 'end_character': 54, 'bleu_score': 0.570674577705599, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4032925258819207620}, 'section': 'Section::::Cast.\n'}]}]