Select a suitable figure from the four alternatives that would complete the…

Concept: In each row of this figure matrix, the third figure is formed by isolating the elements unique to the second figure — the parts that do NOT already appear in the first figure of the same row. Any element common to both the first and second figures cancels out and does not carry through to the third figure.

Application:

1. Row 1: the first figure is a plain triangle. The second figure is the same triangle with an added vertical line through the middle and a small circle at the top-right corner. Removing the triangle, which is common to both, leaves the vertical line with the circle — exactly the third figure given in that row.

2. Row 2: the first figure is a square with one diagonal line. The second figure is the same square and diagonal with an added horizontal and vertical mid-line forming a four-part grid. Removing the square and diagonal, common to both, leaves only the horizontal and vertical mid-lines — a plus sign with no square around it, exactly the third figure given in that row.

3. Row 3 (the row with the missing figure): the first figure is a square with a curved arc near its base. The second figure is the same square and arc with both diagonal lines added, crossing in the middle. Removing the square and the arc, common to both, leaves only the two crossing diagonal lines.

Cross-check: Applying this same rule independently to Row 1 and Row 2 reproduces the figures already given in the matrix, confirming the rule holds; the same rule applied consistently to Row 3 must therefore also hold.

Result: The figure that completes the matrix is two diagonal lines crossing to form an X, with no square outline and no curved arc.