Plugging in

gives the following plot:

http://www.wolframalpha.com/input/?i=x%5E2-y%5E2+%3D+1
Yet, it seems that choice [

**e**] was incorrect according to the answer key. But choice [

**d**] (as per the answer key) gives the following plot:

http://www.wolframalpha.com/input/?i...%2By%5E2+%3D+1
What am I missing?