Question: grey's anatomy what season does christina leave
[{'answer': 'season 10', 'provenance': [{'wikipedia_id': '7687021', 'title': 'Cristina Yang', 'start_paragraph_id': 2, 'start_character': 906, 'end_paragraph_id': 2, 'end_character': 915, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '7687021', 'title': 'Cristina Yang', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 1003, 'bleu_score': 0.9878413801697931, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5972642070641139311}, 'section': 'Section::::Abstract.'}]}]