Question: who has been nominated for the most best actor oscars
[{'answer': 'Jack Nicholson', 'provenance': [{'wikipedia_id': '43842610', 'title': 'List of actors with two or more Academy Award nominations in acting categories', 'start_paragraph_id': 2, 'start_character': 189, 'end_paragraph_id': 2, 'end_character': 203, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]