Solution: From the meaning of the question, △PF 1F2 is a right triangle, and the slope of PF2 is-.

Let |PF 1|=m and |PF2|=n, then,

∫m-n = 2a，m2+n2=4c2，

∴m=2b,n=2a，

mn = 2b2，

∴b=2a，

∴c=a，

∴e==.

Therefore, choose: d.