What format for windows backup?

[BlazednSleepy]

So I have a 2tb external HD and I want to back up both the mac and windows side with the same HD. When I want to partition the HD for windows it gives me these options for what to format it with.

MS-DOS(FAT)
ExFAT
Free Space

What format is best for windows backup?

Any other tips would be great as well.

Thanks.

[BlazednSleepy]

I figured it out

[RightMACatU]

I figured it out
and...?

[NMF]

ExFAT, then format as NFTS in Windows if you want.