Let $A$ be a $3 \times 5$ matrix in row echelon form (REF, not necessarily reduced):\n$A = \begin{bmatrix} 1 & 0 & 2 & 1 & 0 \\ 0 & 3 & 1 & 0 & 1 \\ 0 & 0 & 0 & 5 & 2 \end{bmatrix}$\nWhich of the following correctly identifies the pivot columns?