单选题 Although the project has been approved, many companies find the cost of implementation is prohibitively expensive.
【正确答案】 D
【答案解析】解析：副词词义辨析。prohibitively意为“过高地，过分地”，选项中incredibly(难以置信地，非常地)与其意思相近，且符合句意。故答案为D。