Question: when did california become a territory of the united states
[{'answer': '1848', 'provenance': [{'wikipedia_id': '5407', 'title': 'California', 'start_paragraph_id': 5, 'start_character': 389, 'end_paragraph_id': 5, 'end_character': 393, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5407', 'title': 'California', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 714, 'bleu_score': 0.9069644857060821, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2016860716204932102}, 'section': 'Section::::Abstract.'}]}]