What is the difference from A,B,C cage

What is the difference between the A, B, and C cages?

A-style cage with meshes and trays in standard,and there are water-shedding eaves over the tray, used to direct liquid into the tray below,the grill mesh is put on the water-shedding eave,and the A-stayle cage bottom panel of which is angle welded to the cage body, this is very different from B and C cage.

B-style cage without mesh and tray in standard, and there are full-rounded conners inner, so it is very easy clean and disinfect due to its fully rounded corners.

C-style cage details

C-style cage acturelly is B-cage equipped with a tray and a grille, and it also has fully rounded corners inside. In the following photos, you can see the difference between them.