One way to identify the presence of hidden partitions on a suspect hard drive is to:

A.
Add up the total size of all known partitions and compare it to the total size of the hard drive

B.
Examine the FAT and identify hidden partitions by noting an in the artition Type field

C.
Examine the LILO and note an in the artition Type field

D.
It is not possible to have hidden partitions on a hard drive