的反函数是（   ）

A、<p><img src="http://oapi.open.com.cn/api/core/file/gofile.do?id=PIqeffhTEMP20160910102041497.png&amp;appkey=5da97a028134420c84123474e7e59e93" title="blob.png" alt="blob.png"></p>

B、<p><img src="http://oapi.open.com.cn/api/core/file/gofile.do?id=PIxybboTEMP20160910102101676.png&amp;appkey=5da97a028134420c84123474e7e59e93" title="blob.png" alt="blob.png"></p>

C、<p><img src="http://oapi.open.com.cn/api/core/file/gofile.do?id=PIpgktaTEMP20160910102120385.png&amp;appkey=5da97a028134420c84123474e7e59e93" title="blob.png" alt="blob.png"></p>

D、<p><img src="http://oapi.open.com.cn/api/core/file/gofile.do?id=PIukvyhTEMP20160910102131743.png&amp;appkey=5da97a028134420c84123474e7e59e93" title="blob.png" alt="blob.png"></p>