Shouldnt the correct answer be D, i think even in the video solution gregmat told D only.

At the y=x line, the x coordinate and y coordinate are the same.

Above that line is x bigger or y bigger?

Below that line is x bigger or y bigger?

ya above the line y is bigger and below x is bigger, however in this q it is asking sum of each individual coordinates

So B>A and C>D right?

yes thats true but how will you prove that a+b>c+d

Oh, I think I misread the quantities. That’s a good point, let me think about that.

Hint: coordinate geometry is to scale on the GRE.

Wow, it makes sense now!