Step 1: Integration process.
This integral simplifies after applying standard integration techniques involving exponential and rational functions. The result is \( \frac{e^x}{1 + x^2} + C \).
Step 2: Conclusion.
Thus, the correct answer is option (C).
Final Answer:
\[
\boxed{\text{(C) } \frac{e^x}{1 + x^2} + C}
\]