Question: who sang the song i can only imagine first
[{'answer': 'Christian rock band MercyMe', 'provenance': [{'wikipedia_id': '2867531', 'title': 'I Can Only Imagine (MercyMe song)', 'start_paragraph_id': 1, 'start_character': 34, 'end_paragraph_id': 1, 'end_character': 61, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]