Default [Q] Android Security Hot Topics? Graduation conclusion work.

Hi,

I'm a student from Brazil, and I'm entering in the android security area.
I'm going to do my graduation work in android security, and I'm looking for good topics or themes to talk about.
I choose 4 titles as options, but don't know if they're good enough and "hot topics". Can you tell me what you guys think?

1) Analysis of the security applied to Android
2) Revision of today's forensic methods to mobile focused on Android
3) Data exposition: analysis of the security flaws in Android
4) Exploit and malware analysis for Android.

And, if you let-me ask more, can you send-me some hot topics about android security?

Thank you very much.