Step 1: Concept
When the origin is shifted to a new point $(h, k)$ by translation of axes, the relationship between the original coordinates $(x, y)$ and the new coordinates $(x', y')$ is given by the formulas $x = x' + h$ and $y = y' + k$.
Step 2: Meaning
Here, the shifted origin is $(h, k) = (2, 3)$ and the transformed coordinates of the point $P$ are $(x', y') = (1, -2)$. We need to determine the original coordinates $(x, y)$.
Step 3: Analysis
Using the translation formulas:
\[ x = x' + h = 1 + 2 = 3 \]
\[ y = y' + k = -2 + 3 = 1 \]
Thus, the original coordinates of the point $P$ are $(3, 1)$.
Step 4: Conclusion
The original coordinates of the point $P$ are $(3, 1)$, which corresponds to option (A).
Final Answer: (A)