Affordable Housing Tenure Interview Q

I have an interview tomorrow for a housing company and have to prepare an answer for a set Q (which is 'can you explain (in no more than 3 minutes) your understanding of three different types of affordable housing tenure).
I have done a litte research and come up with rented and shared ownership, however I'm not entirely sure if I'm on the right lines.
I've just graduated from uni and still live with parents so this topic isn't my strongest!
Can someone please point me in the right direction?

Many thanks.

why don't you do a search on the web??
www.propertypath.ie -south dublin council

Maybe it's:
shared ownership
Affordable Housing
Affordable Housing Initiative

Go to a few county councils web pages, they have an explanation on each of the schemes.