it should follow two conditions
1-Trace of matrix = sum of Eigen Values =sum of diagonal
Trace=1+4+3=8
2 -Determinant of given matrix = 12
As we know product of eigen values is determinant of matrix
Now we have to check options
(A) 1, 4, 3 =1+4+3=8 satisfied
(B) 3, 7, 3 =3+7+3=13 Wrong
(C) 7, 3, 2 =7+3+7=17 Wrong
(D) 1, 2, 3 =1+2+3=6 Wrong
So option A is answer