GATE2017: 2

Question

The figure shows a shape $\text ABC$ and its mirror image $\text A_1B_1C_1$ across the horizontal axis $\text (X-axis)$. The coordinate transformation matrix that maps $\text ABC$ to $\text A_1B_1C_1$ is 

• A. $\begin{bmatrix}0&1\\1 &0\end{bmatrix}$
• B. $\begin{bmatrix}0 &1\\-1 &0\end{bmatrix}$
• C. $\begin{bmatrix}-1 &0\\0 &1\end{bmatrix}$
• D. $\begin{bmatrix}1 &0\\0 &-1\end{bmatrix}$