【单选题】
下面哪张线性渐变的图像应用了“镜像”溢出模式（ ）
①
<img src=http://60.205.157.60/course/a@AB815211F70A47FD714B2F8F17BE05CF.png title=image049.png alt=image049.png/>
②
<img src=http://60.205.157.60/course/a@E1DADD5577574442D0162A49BAC4DEC0.png title=image051.png alt=image051.png/>
③
<img src=http://60.205.157.60/course/a@00A50A7CEED91D9D3CA29B281637904F.png title=image053.png alt=image053.png/>
④
<img src=http://60.205.157.60/course/a@6D4069470BA73DFFFEE23ED6D9A31E1E.jpg title=image056.jpg alt=image056.jpg/>