Question: who plays agent romanoff in iron man 2
[{'answer': 'Scarlett Johansson', 'provenance': [{'wikipedia_id': '22144721', 'title': 'Iron Man 2', 'start_paragraph_id': 1, 'start_character': 410, 'end_paragraph_id': 1, 'end_character': 428, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '22144721', 'title': 'Iron Man 2', 'start_paragraph_id': 14, 'start_character': 12, 'end_paragraph_id': 14, 'end_character': 1135, 'bleu_score': 0.983486730120648, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2956454040852783354}, 'section': 'Section::::Cast.\n'}]}]