Sociopath Test!

Here's the test to determine whether or not you are truly a sociopath.
Write your answer in the comments.
[If you know what the "right" answer is, as in you have already heard this and been told, then don't say anything.]

"A woman's mother dies and she goes to the funeral. At the funeral, the woman meets a cute guy. After the funeral, she goes home and kills her sister. Why does she kill her sister?"

Leave your answers in the comments!