Question: when did jeep introduce the 4 door wrangler
[{'answer': '2007', 'provenance': [{'wikipedia_id': '37497879', 'title': 'Jeep Wrangler Unlimited', 'start_paragraph_id': 2, 'start_character': 49, 'end_paragraph_id': 2, 'end_character': 53, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]