Question: what are the three categories associated with the udl framework
[{'answer': 'Multiple means of representation', 'provenance': [{'wikipedia_id': '2800542', 'title': 'Universal Design for Learning', 'start_paragraph_id': 3, 'start_character': 13, 'end_paragraph_id': 3, 'end_character': 45, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Multiple means of expression', 'provenance': [{'wikipedia_id': '2800542', 'title': 'Universal Design for Learning', 'start_paragraph_id': 4, 'start_character': 13, 'end_paragraph_id': 4, 'end_character': 41, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Multiple means of engagement', 'provenance': [{'wikipedia_id': '2800542', 'title': 'Universal Design for Learning', 'start_paragraph_id': 5, 'start_character': 13, 'end_paragraph_id': 5, 'end_character': 41, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]