Question: where was christianity most strongly established by ad 325
[{'answer': 'North Africa and the East', 'provenance': [{'wikipedia_id': '12841324', 'title': 'History of early Christianity', 'start_paragraph_id': 4, 'start_character': 132, 'end_paragraph_id': 4, 'end_character': 157, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Western Europe and the Mediterranean Basin'}]