Question: when did the us drop the atomic bomb on hiroshima
[{'answer': 'August 6 , 1945', 'provenance': [{'wikipedia_id': '11778948', 'title': 'Atomic bombings of Hiroshima and Nagasaki', 'start_paragraph_id': 63, 'start_character': 749, 'end_paragraph_id': 63, 'end_character': 764, 'bleu_score': 1.0, 'section': 'Section::::Hiroshima.:Hiroshima during World War II.\n'}]}]