Which drawing (a) to (d) is the front view of this stack, looking in the direction of the arrow?

For each line from front to back take the taller column: $\max (1,3)=3,\max (2,1)=2,\max (1,2)=2,\max (0,1)=1$. So 3, 2, 2, 1: (c). (a) shows only the front row, (b) is the back view and (d) the side view.