Again this is a simple question with only one answer. Since you are applying for this job, you must already have an idea about what this job position is looking for.
The expectations of this job position may not change based on your reply to this question. So it is not a good idea to tell a lot of your preferences about this job position. Rather you can counter it by asking a counter question.
You can pick the points from Job posting and use it in your answer.
Sample answer is:
I have been looking for growing my career in Mobile commerce and Cloud computing. I want work in an organization where I can learn this domain. I find that this position is in this domain. I already have technical expertise to work in this domain. I find this is a great opportunity for me to use my technical expertise in learning this domain and delivering business value.