Will you be happy to re-locate, if required?

Again, a question for you to answer based on your position. If you are anticipating this question in the interview, it is better to discuss this with your family also before you go to face the interview.

Also be specific what relocation means to you. For example Banking & Insurance Industry is expanding into Villages and small towns and need urban qualified executives there. So does many other services industry. Moreover Manufacturing units are located in far off distant places and organizations prefer people with flexibility to move around in their markets and business locations without any rigidity.