关于sale和purchase的词语辨析

The conflict has been surfacing since 2002, when the corporation bought Vermont’s only nuclear power plant, an aging reactor in Vernon. As a condition of receiving state approval for the sale, the company agreed to seek permission from state regulators to operate past 2012.　

[D] get permission to purchase a power plant.答案解释说sale和purchase是可以替换的？
这不是一个买进，一个售出的意思么？