Both a and b are correct.
For example, on WB3:
If you partition only the first 4GB of a HD with 2.1GB partitions or less on plain OS3.1 or less, things will work and the rest of the drive will go to waste.
Then again, if you try to partition the whole drive with bigger partitions, your system will become very badly screwed up.
I would say it would be the same principle for WB2.
