Question: who sang the theme song for the wonder years
[{'answer': 'Joe Cocker', 'provenance': [{'wikipedia_id': '142892', 'title': 'The Wonder Years', 'start_paragraph_id': 50, 'start_character': 70, 'end_paragraph_id': 50, 'end_character': 80, 'bleu_score': 1.0, 'section': 'Section::::Title sequence.\n'}]}]