Half marks.
C-clip is a "semi-floating" axle - the inner end bearing rides on the differential carrier, as with a "retainer plate" SF axle. However if you lose a C-clip, you lose the wheel (since that's what holds it in place.) Also, the wheel end bearing rides directly on the shaft, so if the shaft bearing surface is toast, replace the shaft.
"Retainer plate" style has a pressed-on wheel end bearing, a "floating" inner end, but the shaft is held in place by a retainer plate bearing against the seal and bearing. The wheel bearing does not ride on the shaft, but it is pressed on, so there's still some need for a shaft in good condition. Breaking a shaft, you still have better than even odds of keeping the wheel in place until you can replace the shaft.
"Full-floating" shafts don't bear weight of the vehicle - and bearings don't ride on them or are installed on them. The inner end is carried and borne by the differential carrier and bearings, and the outer end is screwed to a hub. The shaft may be removed entirely, and the wheel will stay put. The wheel end bearings are carried in the hub, and don't have anything at all to do with the shaft.
The first two sorts are semi-floating axles. A "non-floating" axle shaft would be a shaft that bears the weight of the vehicle, and bearings at both ends ride on the shaft (either on a hardened and ground journal, or on an inner race pressed onto a size-controlled section.)