Step 1: Note that in both patterns P and Q, the white regions are transparent. This means only the coloured regions block visibility when the patterns are overlapped.
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Step 2: Place pattern Q directly over pattern P without rotation. Wherever Q has transparent (white) regions, the underlying pattern P will remain visible.
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Step 3: Analyze the overlap:
\begin{itemize}
\item Black regions from P remain visible unless covered by coloured regions of Q,
\item Brown regions from Q appear wherever they lie over transparent areas of P,
\item The final pattern is a composite of visible black and brown shapes.
\end{itemize}
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Step 4: Compare each option with the expected composite:
\begin{itemize}
\item Options A, B, D: Show incorrect masking or misplaced coloured regions.
\item C: Correctly represents all overlaps and transparent regions — valid.
\end{itemize}
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Final Answer:
\[
\boxed{C}
\]
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