Question: who sings i ain't mad at cha
[{'answer': '2Pac', 'provenance': [{'wikipedia_id': '6955261', 'title': "I Ain't Mad at Cha", 'start_paragraph_id': 1, 'start_character': 41, 'end_paragraph_id': 1, 'end_character': 45, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]