Question: when did comic con start in san diego
[{'answer': 'March 21 , 1970', 'provenance': [{'wikipedia_id': '843158', 'title': 'San Diego Comic-Con', 'start_paragraph_id': 6, 'start_character': 398, 'end_paragraph_id': 6, 'end_character': 413, 'bleu_score': 1.0, 'section': 'Section::::History and organization.\n'}]}]