Unbonded (first one) is the CSP degree which doesn't require any sort of legal contract (bond) with the Government.
The second one on the other hand does, and requires that one works in a rural designated area upon the completion of the medical degree for as long as the degree itself i.e. 5 years. I think you have something like 10-15 years to 'work' this off - but there's also the option of 'paying' off this agreement. They may have changed this for the future, however. If I'm not mistaken, they're shortening this bond to a single year, but I'm not exactly sure.
The last one, extended rural cohort, is basically like the first one except instead of having the ability to preference between metro/rural placements, one must undergo placements in rural areas i.e. basically half of the degree.
Hopefully that's all correct.