Question 7

Examining the views in Panel I on a $3 \times 3$ base:

1. From the Top View, the front-right corner cell is missing (cut out), and the middle-front and middle-center cells lie on the same flat horizontal step (forming an L-shaped face of height $1$). This immediately eliminates (i) (which has no front-right cutout) and (ii) (where the middle-center cell is raised to height $2$ instead of being coplanar with the height-$1$ step).
2. From the Front View, only the leftmost column reaches height $3$, while the middle and right columns at the back have height $2$ (forming a $2 \times 1$ horizontal rectangle). This eliminates (iii) (where the middle-back column also rises to height $3$). Structure (iv) matches both the Front View and the Top View.