Question: what does acd mean in a call center
[{'answer': 'automatic call distributor', 'provenance': [{'wikipedia_id': '40749', 'title': 'Automatic call distributor', 'start_paragraph_id': 1, 'start_character': 57, 'end_paragraph_id': 1, 'end_character': 83, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '40749', 'title': 'Automatic call distributor', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 657, 'bleu_score': 0.979896933041101, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5626760218530785390}, 'section': 'Section::::Abstract.'}]}]