Question: the most common stone tool type from the acheulean industry is
[{'answer': 'hand - axes', 'provenance': [{'wikipedia_id': '445261', 'title': 'Acheulean', 'start_paragraph_id': 47, 'start_character': 60, 'end_paragraph_id': 47, 'end_character': 70, 'bleu_score': 1.0, 'section': 'Section::::Acheulean tool users.\n'}]}]