Question: what does dd stand for in the navy
[{'answer': 'Destroyer', 'provenance': [{'wikipedia_id': '14090', 'title': 'Hull classification symbol', 'start_paragraph_id': 29, 'start_character': 215, 'end_paragraph_id': 29, 'end_character': 224, 'bleu_score': 1.0, 'section': 'Section::::United States Navy hull classification codes.\n'}]}, {'provenance': [{'wikipedia_id': '14090', 'title': 'Hull classification symbol', 'start_paragraph_id': 29, 'start_character': 0, 'end_paragraph_id': 29, 'end_character': 306, 'bleu_score': 0.958740481558872, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11602539929613423309}, 'section': 'Section::::United States Navy hull classification codes.\n'}]}]