Complete the following figure matrix.

The correct option is the figure showing the rectangle with both the top and right triangular regions shaded with diagonal lines (corresponding to the option with diagonal shading).

Let us analyze the pattern in the figure matrix row by row:

1. Pattern in Row 1:
- The first cell contains a large triangle divided into 4 smaller triangular regions (with 0 shaded regions).
- The second cell has 1 region shaded (the top small triangle).
- The third cell has 2 regions shaded (the top small triangle and the adjacent central inverted triangle).
- The shading consists of horizontal lines.

2. Pattern in Row 2:
- The first cell contains a circle divided into 4 quadrants (with 0 shaded quadrants).
- The second cell has 1 quadrant shaded (the top-right quadrant).
- The third cell has 2 quadrants shaded (the top-right and the bottom-right quadrants, making the entire right half shaded).
- The shading consists of horizontal lines.

3. Pattern in Row 3 (Missing Figure):
- The first cell contains a rectangle divided into 4 triangular regions by its diagonals (with 0 shaded regions).
- The second cell has 1 region shaded (the top triangular region) with diagonal (slanted) lines.
- Following the established pattern, the third cell must have 2 adjacent regions shaded (the top and the right triangular regions).
- Since the shading in the second cell of this row uses diagonal lines, the shading in the third cell must also consist of diagonal lines to maintain consistency.

Comparing the options, the figure that satisfies these conditions—having the top and right triangular regions shaded with diagonal lines—is the correct choice.