Today an interviewer from Riyadh (KSA) asked me about my relationship and Girlfriend which i dont have. I was shocked. Is it right or wrong to ask?

Maybe, just maybe, part of the job description of which you are applying for involves travel and/or relocation. Relationship status sometimes affects the decision of the candidate in pursuing a career.

Basm Allah Alrahman Alrahim

you send me a request to answer this question ? !

that's strange ? why ? because I am a Muslim and I don't believe that there is something called girl friend or boy friend , those2 must be deleted from dictionary not here but in all the world 

replace girl friend with Engaged or future wife

If I were asked about my future wife , I will say consider that my future wife is your sister , would you ask me about here ? !

Why The word Girl Friend must be deleted from all the world ?

Because when any relation between a girl and a man became more than talk before marriage  the Instinct will make both make wrong decision a bout there future life , consider that you are thirsty and you are a desert and you see a glass that contain anything will you think is it wrong or right to drink it ? ! 

so between man and woman the brain must be with full functionality to make the right family ?