Question: what are the main sources of vitamin k
[{'answer': 'green leafy vegetables', 'provenance': [{'wikipedia_id': '32541', 'title': 'Vitamin K', 'start_paragraph_id': 3, 'start_character': 94, 'end_paragraph_id': 3, 'end_character': 116, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '32541', 'title': 'Vitamin K', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 416, 'bleu_score': 0.972782728923768, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10826186668761668959}, 'section': 'Section::::Abstract.'}]}]