Question: who led the first overland expedition to san diego
[{'answer': 'Fernando Rivera', 'provenance': [{'wikipedia_id': '2998199', 'title': 'Portolá expedition', 'start_paragraph_id': 18, 'start_character': 8, 'end_paragraph_id': 18, 'end_character': 23, 'bleu_score': 1.0, 'section': 'Section::::Expedition.:Baja California to San Diego.:Two groups by land.\n'}]}, {'provenance': [{'wikipedia_id': '2998199', 'title': 'Portolá expedition', 'start_paragraph_id': 18, 'start_character': 0, 'end_paragraph_id': 18, 'end_character': 962, 'bleu_score': 0.888602964797612, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14157855667685278974}, 'section': 'Section::::Expedition.:Baja California to San Diego.:Two groups by land.\n'}]}]