Question: who sang the theme tune to dear john
[{'answer': 'Joan Baxter', 'provenance': [{'wikipedia_id': '4858881', 'title': 'Dear John (British TV series)', 'start_paragraph_id': 26, 'start_character': 224, 'end_paragraph_id': 26, 'end_character': 235, 'bleu_score': 1.0, 'section': 'Section::::Title music.\n'}]}]