Choose the box that is similar to the box formed from the given sheet of…

Concept: In a cuboid net, a cell's own proportions (its width relative to the row's height) fix which face-shape it becomes once folded — cells of one width become one shape (e.g. a near-square pair), cells of a different width become a different shape (an elongated pair). Two SAME-shaped faces of the same shading that are OPPOSITE each other can never be seen together in one three-face view of the finished box; but a shaded face and a DIFFERENTLY-shaped shaded face that are NOT opposite (merely adjacent) can legitimately appear together. So telling a genuine folding from a fake one needs matching face SHAPE, not just color.

Applying this to sheet (X):

1. Measuring the row of four cells (1-2-3-4, left to right): cells 2 and 4 are about twice as wide as cells 1 and 3, and each is roughly as wide as the row is tall — so cells 2 and 4 fold into the pair of SQUARE faces (cell 2 white, cell 4 shaded). Cells 1 and 3 are the narrow cells — they fold into the pair of tall, narrow RECTANGULAR faces (both white).

2. The Top and Bottom flaps (hinged above and below cell 2) are as wide as cell 2 but only about half as tall — they fold into the pair of short, wide RECTANGULAR faces (both shaded).

3. By position in the net, opposite pairs are: cell 1 opposite cell 3 (the two white narrow rectangles), cell 2 opposite cell 4 (the square pair, one white one shaded), and Top opposite Bottom (the two shaded short-wide rectangles).

4. So there are two DIFFERENTLY-shaped shaded faces that are not opposite each other: cell 4 (the shaded square) and either flap (a shaded short-wide rectangle) — these two CAN sit side by side in a valid view. But Top and Bottom are both the SAME shape and shading and ARE opposite each other, so they can never be shown together.

Cross-check against the four figures:

• Figure (4) shows all three visible faces shaded — zero white faces. Only 3 of the 6 faces of (X) are shaded, and one of the always-white cell-1/cell-3 pair must appear in every view, so a picture with no white face at all is impossible.

• Figure (2) shows its two shaded faces sitting directly together as a matching pair of the same short-wide rectangular shape — exactly the Top-and-Bottom-together case that can never happen, since Top and Bottom are opposite faces. Impossible.

• Figure (1) and figure (3) each keep one white face visible, and wherever two shaded faces appear together they are of two DIFFERENT shapes (the square cell-4 face plus one flap) rather than the same rectangular flap-shape repeated — both are consistent foldings of sheet (X).

So only the cuboids shown in figures (1) and (3) can be formed from sheet (X).