单项选择题
A.<br /><img src="https://imgtest.ppkao.com/ExamPaperRes/2014/8/27/4404003553f645e5bc3b9d5dee1ad6f8/4e58f191-5b84-441c-8137-5a7cfd3a29a8.jpg">
B.<br /><img src="https://imgtest.ppkao.com/ExamPaperRes/2014/8/27/4404003553f645e5bc3b9d5dee1ad6f8/89c7ee57-3bdf-4bae-9343-bb20d97753b2.jpg">
C.<br /><img src="https://imgtest.ppkao.com/ExamPaperRes/2014/8/27/4404003553f645e5bc3b9d5dee1ad6f8/171eb562-2fd3-4f3c-9a2c-6a3f1c8f9f0d.jpg">
D.<br /><img src="https://imgtest.ppkao.com/ExamPaperRes/2014/8/27/4404003553f645e5bc3b9d5dee1ad6f8/6a7e833f-1ed5-4b14-ba12-d2172a788709.jpg">