A、lnx+C
B、ln（x+C）
C、<img width="78" height="21" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/6d4875d3-1673-4d5a-83dd-d32dd0abb7df.png" />
D、<img width="78" height="20" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/4428067f-5805-4a16-83b6-5414e4894fb5.png" />