Two equations and 3 variables

Another problem from the GRE program. Determine which option is greater:

x = v + 2

y = 2v

Option A: x^2 + y^2

Option B: (x+y)^2

I decided that B is greater because it results in: x^2 + y^2 + 2xy. So I guess that this 2xy makes the possitive difference. However, I have tried it out with v=1 and v=-1 and both of them are ok with my result, B is greater. However, in the corrections it says that it canīt be determined which one is greater. Could anyone help me to know why??

Thank you so much!