Question: who built the track of the transcontinental railroad track that began in sacramento california
[{'answer': 'The Western Pacific Railroad Company', 'provenance': [{'wikipedia_id': '36541', 'title': 'First Transcontinental Railroad', 'start_paragraph_id': 1, 'start_character': 553, 'end_paragraph_id': 1, 'end_character': 589, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'The Union Pacific', 'provenance': [{'wikipedia_id': '36541', 'title': 'First Transcontinental Railroad', 'start_paragraph_id': 1, 'start_character': 817, 'end_paragraph_id': 1, 'end_character': 834, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'The Central Pacific Railroad Company of California'}, {'provenance': [{'wikipedia_id': '36541', 'title': 'First Transcontinental Railroad', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 942, 'bleu_score': 0.7894936104282461, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16205201320816559482}, 'section': 'Section::::Abstract.'}]}]