Question: what is the center of a trampoline called
[{'answer': "`` bounce mat ''"}, {'answer': "`` trampoline bed ''", 'provenance': [{'wikipedia_id': '645580', 'title': 'Trampoline', 'start_paragraph_id': 24, 'start_character': 127, 'end_paragraph_id': 24, 'end_character': 143, 'bleu_score': 1.0, 'section': 'Section::::Types of trampolines.\n'}]}, {'provenance': [{'wikipedia_id': '645580', 'title': 'Trampoline', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 212, 'bleu_score': 0.9451524926983921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3694746022720449356}, 'section': 'Section::::Abstract.'}]}]