Steps to calculate the Eigenvalues:-
1. Write the matrix in the form of "determinant(A - lambda * I)".
2. Find the characteristic equation and put it equal to 0.
3. Find the root of the characteristic equation and the roots are eigenvalues.
Now, in this case, we are getting characteristic equation as:-
x2 - 8x + 15 = 0
On solving we will get x = 3,5 which are the eigenvalues of the characteristic equation.
Hence option C) 3,5 is the answer.