dont know but i think its based on the installer that mandriva one (the installable livecd) has. If you do expert mode i think you ought to be able to choose.

cds? it should be one disk?

theres the old (stable version) then there is the new 2007 release candidate one - thats the one most people are on (but its buggy so take my advice and take the older version as apt-get dist-upgrade ought to be able to upgrade it later)