The shaded image in figure A is larger.
Which shaded region is larger?
First, notice that the four white corners are exactly the same in both images, this just means that the larger image will contain the larger figure.
Image A is 2 units by 5 units, for a total of:
2*5 = 10 square units.
Figure B is 3 by 3 units, for a total of:
3*3 = 9 square units.
Then if image A is larger, and the white regions are equal in both images, this means that the shaded figure in image A must be larger than the shaded image in figure B.