a jehovah witness asks a boy sitting outside a house playing on his phone if his parents are home..

"yes they are" says the boy without looking.
The jehovah witness knocks on the door for a while and nobody comes out, so he asks the boy: "Are you sure your parents are home?"
yes i'm sure says the boy.
After knocking on the door again and after no getting a response the man says "Are you really sure that your parents are home?"
"Yes i'm sure" says the boy.
"so, how come your parents don't answers the door?"
without looking the boy says "because that's not my house"