Question: who plays the hulk in the avengers age of ultron
[{'answer': 'Mark Ruffalo', 'provenance': [{'wikipedia_id': '36484254', 'title': 'Avengers: Age of Ultron', 'start_paragraph_id': 1, 'start_character': 430, 'end_paragraph_id': 1, 'end_character': 442, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '36484254', 'title': 'Avengers: Age of Ultron', 'start_paragraph_id': 14, 'start_character': 0, 'end_paragraph_id': 14, 'end_character': 1076, 'bleu_score': 0.9636844770794871, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2282755752034766575}, 'section': 'Section::::Cast.\n'}]}]