Question: who played nancy on nightmare on elm street
[{'answer': 'Heather Langenkamp', 'provenance': [{'wikipedia_id': '4511532', 'title': 'Nancy Thompson (A Nightmare on Elm Street)', 'start_paragraph_id': 1, 'start_character': 115, 'end_paragraph_id': 1, 'end_character': 133, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Rooney Mara', 'provenance': [{'wikipedia_id': '4511532', 'title': 'Nancy Thompson (A Nightmare on Elm Street)', 'start_paragraph_id': 1, 'start_character': 178, 'end_paragraph_id': 1, 'end_character': 189, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]