Question: what character does karen gillan play in avengers
[{'answer': 'Nebula', 'provenance': [{'wikipedia_id': '23002288', 'title': 'Karen Gillan', 'start_paragraph_id': 1, 'start_character': 235, 'end_paragraph_id': 1, 'end_character': 241, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]