Concept:Since A is non-singular, A−1 exists and can be used to simplify the given matrix equation.Explanation:The given equation is A2−A+I=0.Multiply both sides by A−1 on the left:A−1(A2−A+I)=A−1⋅0This gives:A−1A2−A−1A+A−1I=0Now simplify each term:A−1A2=A,A−1A=I,A−1I=A−1Substitute these into the equation:A−I+A−1=0Rearrange to isolate A−1:A−1=I−AAnswer:A−1=I−AHence, the correct option is C. I−A.