Question: who plays as nebula in guardians of the galaxy
[{'answer': 'Karen Gillan', 'provenance': [{'wikipedia_id': '23002288', 'title': 'Karen Gillan', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 12, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]