The standard organization consists of the following structural units:
level 1 (a), (b), (c), etc.
level 2 (1), (2), (3), etc.
level 3 (i), (ii), (iii), etc.
level 4 (A), (B), (C), etc.
level 5 (1), (2), (3), etc.
level 6 (i), (ii), (iii), etc.
1 C.F.R. § 21.11