Question: who does stan smith voice on american dad
[{'answer': 'Seth MacFarlane', 'provenance': [{'wikipedia_id': '2082680', 'title': 'List of American Dad! characters', 'start_paragraph_id': 6, 'start_character': 34, 'end_paragraph_id': 6, 'end_character': 49, 'bleu_score': 1.0, 'section': 'Section::::Main characters.:Stan Smith.\n'}]}]