如何只更改角度单选按钮的特定颜色？

I have crated angular application for examination in which user gives exam and finally show full report with selected answer I have used ng-repeat for radio button to show options and I want to show user has selected answer and corrected answer if user has selected wrong than its should be red else green but it I have checked using conditions but it changing all radio button colors here is codeI have crated angular application for examinati