Question: what does ds stand for in uk police
[{'answer': 'detective sergeant', 'provenance': [{'wikipedia_id': '631179', 'title': 'Criminal investigation department', 'start_paragraph_id': 33, 'start_character': 312, 'end_paragraph_id': 33, 'end_character': 330, 'bleu_score': 1.0, 'section': 'Section::::By country.:United Kingdom.\n'}]}]