Question: what is the meaning of ac dc current
[{'answer': 'Alternating current', 'provenance': [{'wikipedia_id': '42986', 'title': 'Alternating current', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 19, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'direct current', 'provenance': [{'wikipedia_id': '42986', 'title': 'Alternating current', 'start_paragraph_id': 1, 'start_character': 102, 'end_paragraph_id': 1, 'end_character': 116, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '42986', 'title': 'Alternating current', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 611, 'bleu_score': 0.9638930762749001, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12562883655422100862}, 'section': 'Section::::Abstract.'}]}]