In Panel I of the figure below, the front view and top view of a structure are shown. Which one of the 3D structures shown in Panel II possesses the views shown in Panel I?
Show Hint
Match the front view outline first to eliminate options, then confirm with the top view.
Step 1: Fix the rule for matching a 3D block structure to its views.
A block structure is correct only if looking at it from the front gives the exact front view outline and looking at it from directly above gives the exact top view outline, both at the same time. A structure that matches only one of the two views is not the answer.
Step 2: Start with the top view this time.
Panel I's top view has a specific footprint with a notch cut into it. Any candidate whose footprint from above is a plain rectangle or is missing that notch can be dropped right away, since the footprint of a structure never changes no matter which way you look at it from the side.
Step 3: Drop the options whose footprint is wrong.
Options (i) and (ii) both change the footprint, one by shifting a cube out of the notch area and one by adding a cube where Panel I has none. Neither reproduces the top view of Panel I, so both are out.
Step 4: Compare the remaining candidates using the front view.
Between the structures left standing, their side placement differs from Panel I once we look from the front. Structure (iii) places a cube one step back, which changes the staircase pattern of the front view, so its front outline no longer matches Panel I.
Step 5: Confirm the last candidate.
Structure (iv) is the one candidate left once the wrong top views and the wrong front view are removed. Checking it directly against Panel I, both its top view notch and its front view staircase line up exactly.
Step 6: State the result.
Working from the top view down to the front view leads to the same single answer.
\[ \boxed{\text{(iv)}} \]
