Question: who sang lead on 25 or 6 to 4
[{'answer': 'Peter Cetera', 'provenance': [{'wikipedia_id': '6728416', 'title': '25 or 6 to 4', 'start_paragraph_id': 1, 'start_character': 179, 'end_paragraph_id': 1, 'end_character': 191, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6728416', 'title': '25 or 6 to 4', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 521, 'bleu_score': 0.8575953367669531, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11608538429614183623}, 'section': 'Section::::Abstract.'}]}]