Question: who played the oldest brother in malcolm in the middle
[{'answer': 'Christopher Masterson', 'provenance': [{'wikipedia_id': '299121', 'title': 'Malcolm in the Middle', 'start_paragraph_id': 6, 'start_character': 354, 'end_paragraph_id': 6, 'end_character': 375, 'bleu_score': 1.0, 'section': 'Section::::Premise.\n'}]}]