There's no right answer to this - they'll all have pros and cons.
If you need any offline capability then you'll need to use Hybrid or Native - while HTML5 does have some capability to store data its not practical to secure it at the moment. This would most likely be the fastest to develop and it means that you don't have to release new versions etc, as your users will automatically access the latest version. HTML5 might be painful over 3G though - it all depends on the volumes of data, size of pages, quality of coverage etc.
If it needs to be super fast and slick, or needs access to device features that aren't avilable, then native is the probably the best option. You will need android developer skills though.