Question: what is the families last name on this is us
[{'answer': 'Pearson', 'provenance': [{'wikipedia_id': '50526957', 'title': 'This Is Us (TV series)', 'start_paragraph_id': 6, 'start_character': 129, 'end_paragraph_id': 6, 'end_character': 136, 'bleu_score': 1.0, 'section': 'Section::::Premise.\n'}]}]