Question: who sang the original happy days theme song
[{'answer': 'Pratt & McClain', 'provenance': [{'wikipedia_id': '39675028', 'title': 'Happy Days (TV theme)', 'start_paragraph_id': 2, 'start_character': 431, 'end_paragraph_id': 2, 'end_character': 446, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]