If there are any other partitions that need to be deleted, you can do so at this time.
For example, the Windows 7 installation I had on my PC previously created this special 100MB (very small) partition to store system data in. This is most definitely related to the operating system that I'm trying to completely remove from my computer so I'll delete this as well.
Highlight the partition and click the Delete link.
Note: As you can see, the partition we deleted in the last step is gone. It may appear like it's still there but if you look closely, you'll see that that same 29.9GB space is now described as Unallocated Space, not as a partition.