Step 1: Split the integral.
Since the absolute value function changes sign at \( x = 3 \), split the integral into two parts: one from 1 to 3, and another from 3 to 4, then integrate each part separately.
Step 2: Conclusion.
Thus, the correct answer is option (B).
Final Answer:
\[
\boxed{\text{(B) } \frac{5}{2}}
\]