Step 1: Concept
Combine like terms by finding a common denominator.
Step 2: Meaning
The LCM of 1, 4, and 3 is 12.
Step 3: Analysis
$\frac{12x + 3x + 4x}{12} < 13 \implies \frac{19x}{12} < 13 \implies 19x < 156$.
Step 4: Conclusion
$x < \frac{156}{19}$, which in interval notation is $(-\infty,\frac{156}{19})$.
Final Answer: (A)