Step 1: Concept
Product $XY$ is defined if the number of columns in $X$ equals the number of rows in $Y$.
Step 2: Meaning
Order of $A = 3 \times 3$, $B = 3 \times 2$, $C = 3 \times 1$.
Step 3: Analysis
Product $AB$: $(3 \times 3) \times (3 \times 2) \to$ defined, result is $3 \times 2$.
Product $(AB)C$: $(3 \times 2) \times (3 \times 1)$. Number of columns (2) $\ne$ number of rows (3).
Step 4: Conclusion
$(AB)C$ is not defined.
Final Answer: (D)