Question: how did derek die on grey's anatomy 2015
[{'answer': 'a fatal car accident', 'provenance': [{'wikipedia_id': '7619908', 'title': 'Derek Shepherd', 'start_paragraph_id': 12, 'start_character': 35, 'end_paragraph_id': 12, 'end_character': 55, 'bleu_score': 1.0, 'section': 'Section::::Storyline.\n'}]}, {'provenance': [{'wikipedia_id': '7619908', 'title': 'Derek Shepherd', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 863, 'bleu_score': 0.936477622595786, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16122264006984671540}, 'section': 'Section::::Storyline.\n'}]}]