For most positions this topic should not even occur. It should only be relevant to roles in which travel or regular relocation is part and parcel of the job. If this is posed to you and seems somewhat unusual, then this may be a warning sign. There may be company plans in the future which could prove a factor in your accepting this position if offered it. If this would be an inconvenience to you, take a mental note of this topic and return to it later in the interview when it is your turn to ask a few questions.
- Are you prepared to relocate?
If you are, say so. If you do not want to move, then you do not have to accept the job. Either way try to come across as someone who is positive.
- Are you willing to travel?
Again if you are, say so. You want to sound positive, so find out how much travelling is involved before you turn down the job.