单项选择题

A.(-1,1)
B.(-2,2)
C.<br /><img src="https://imgtest.ppkao.com/ExamPaperRes/2018/2/27/5d8f82cae8d84bf49ad0f2ee760195c6/a923200e-d565-41aa-a02f-25c91eb8d117.jpg">
D.(-∞,+∞)