Answer
1 and 3
Work Step by Step
The singular values of the matrix are the square roots of the eigenvalues of $A^TA$.
$A^TA=\begin{bmatrix}
1&0\\0&-3
\end{bmatrix}\begin{bmatrix}
1&0\\0&-3
\end{bmatrix}=\begin{bmatrix}
1&0\\0&9
\end{bmatrix}$. The eigenvalues are 1 and 9, so the singular values are 1 and 3.