Dell disk drives P/N confusion

Hello,

I need 900 GB WD9001BKHG hard drives for my MD3220.
I looked at the Support Matrix pdf, and found that I needed disk drives with Dell P/N 4X1DR.

But my sellers have disk drives with completely different P/N's!
Their P/N's look like:

400-22929

400-22932

400-22934

400-22975

400-24104

400-24204

400-AEZD

Why the P/N's differ?
Which Part Number is right for me?