Question: who plays the hulk in the avengers movies
[{'answer': 'Mark Ruffalo', 'provenance': [{'wikipedia_id': '22114132', 'title': 'The Avengers (2012 film)', 'start_paragraph_id': 1, 'start_character': 497, 'end_paragraph_id': 1, 'end_character': 509, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '22114132', 'title': 'The Avengers (2012 film)', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 1800, 'bleu_score': 0.994126221360011, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8683706033042927355}, 'section': 'Section::::Cast.\n'}]}]