Question: when did mcdonald's first start serving breakfast
[{'answer': '1972', 'provenance': [{'wikipedia_id': '5671742', 'title': "History of McDonald's", 'start_paragraph_id': 17, 'start_character': 131, 'end_paragraph_id': 17, 'end_character': 135, 'bleu_score': 1.0, 'section': 'Section::::1960s and 1970s.\n'}]}, {'provenance': [{'wikipedia_id': '5671742', 'title': "History of McDonald's", 'start_paragraph_id': 18, 'start_character': 0, 'end_paragraph_id': 18, 'end_character': 460, 'bleu_score': 0.9321992460304711, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5335186561686469004}, 'section': 'Section::::1960s and 1970s.\n'}]}]