Step 1: Solve the integral.
Use the substitution \( u = x^2 + 4 \) to solve the integral.
Step 2: Conclusion.
Thus, the solution to the integral is \( \frac{1}{2\sqrt{2}} \tan^{-1} \left( \frac{x^2 - 4}{2\sqrt{2}} \right) + c \).
Final Answer:
\[
\boxed{A}
\]