Question: who has won the most oscars for costume design
[{'answer': 'Edith Head', 'provenance': [{'wikipedia_id': '62008', 'title': 'Academy Award for Best Costume Design', 'start_paragraph_id': 13, 'start_character': 15, 'end_paragraph_id': 13, 'end_character': 25, 'bleu_score': 1.0, 'section': 'Section::::Multiple nominations.\n'}]}]