I would ignore the diagram.
We know that statement 1 doesn't work, because we just have ratios for 3 of the 5 potential areas, but not an actual area measurement for any of the 3 areas.
Statement 2 doesn't work, since we're just given the area of A with no relation to D.
If we combined them, we know the remaining area of the bottom half is 800 (based on statement 2). So we can setup an equation like
B + C + D + X = 800, where x is the unlabeled part.
Given statement 1, we know the C = .5B and D = .5C
So the new equation is B + .5B + .25B + X = 800. Still, we don't know anything about X.
This was a very tricky diagram that's sole purpose is to confuse you. It doesn't help that the question does NOT mention that the diagram is not drawn to scale (and actually cites "in the figure above"). Seems doubly-misleading.
Imagine if you resized the diagram so that B, C and D only took up 1/4 of the entire lot, as opposed to (what it appears like) 7/16 of the lot. That X term would then equal the other quarter of the diagram.