Step 1 - We choose to expand across the second column, as directed.
Step 2 - We now form the minors for each entry in the second column.
The minor of the 1,2 entry is the determinant of the submatrix formed by removing the first row and second column: $$\begin{vmatrix} 2 & 0 \\1 & 3\end{vmatrix}.$$
The minor of the 2,2 entry is the determinant of the submatrix formed by removing the second row and the second column: $$\begin{vmatrix} 1 & 0 \\1 & 3\end{vmatrix}.$$
The minor of the 3,2 entry is the determinant of the submatrix formed by removing the third row and the second column: $$\begin{vmatrix} 1 & 0 \\2 & 0\end{vmatrix}.$$
Step 3 - We can write the minor and cofactor expansion along the second column: