Say X=-10 and Y=5
so from A -50>-2 ...FALSE
B) XY>1 so, X and Y both can be +ve or -ve (even we can take fractions)
Say X=-10 and Y=-5
Say X=10 and Y=5
So B alone is sufficient to answer.
I've just started looking at GMAT math for the first time in about 10 years, but I'm confused - how can we have a positive fraction if X is -10 and Y is 5? Wouldn't that give us -2/1 effectively?