Question: when does derek and meredith get back together season 4
[{'answer': 'Freedom', 'provenance': [{'wikipedia_id': '11058032', 'title': "Grey's Anatomy (season 4)", 'start_paragraph_id': 66, 'start_character': 1635, 'end_paragraph_id': 66, 'end_character': 1642, 'bleu_score': 1.0, 'section': 'Section::::Reception.\n'}]}]