About 3D augmentation

[TshellT]

'data' value must have shape (b, c, x, y, z) for 3D, but I don't know what do x, y, z stand for respectively.
I saw some other code, use z as the depth of 3D image. Also saw some other code, x as the depth of 3D image.
Can you tell me the answer.
Looking forward your reply, Thank you!