Integrate :$\int \limits_6^8 \large\frac{[x^2]}{[x^2-28 x +196]+[x^2]}$$dx$

Question

$$\begin {array} {1 1} (a)\;1 \\ (b)\;\frac{3}{4} \\ (c)\;4 \\ (d)\;3 \end {array}$$