Question: last name of the british officer sent to drive the french out of the ohio river valley
[{'answer': 'Forbes', 'provenance': [{'wikipedia_id': '2074514', 'title': 'Battle of Fort Duquesne', 'start_paragraph_id': 2, 'start_character': 111, 'end_paragraph_id': 2, 'end_character': 117, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2074514', 'title': 'Battle of Fort Duquesne', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 639, 'bleu_score': 0.9815648442794911, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13717202746432730006}, 'section': 'Section::::Abstract.'}]}]