Step 1: Solving the integral.
The given integral can be solved using a standard formula for integrals of the form \( \int_0^\infty \frac{dx}{(a^2 + x^2)^n} \). Applying this, we get the value \( \frac{231}{2048} \).
Step 2: Conclusion.
Thus, the correct answer is option (D).
Final Answer:
\[
\boxed{\text{(D) } \frac{231}{2048}}
\]