Question: who plays zach in the big bang theory
[{'answer': 'Brian Thomas Smith', 'provenance': [{'wikipedia_id': '30889440', 'title': 'Brian Thomas Smith', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 18, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '30889440', 'title': 'Brian Thomas Smith', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 337, 'bleu_score': 0.9669306597086381, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 960487944583486941}, 'section': 'Section::::Abstract.'}]}]