Which logical storage relationship is correct?

A.
Tablespace< Segment < Extent < Oracle Datablock

B.
B) Segment < Extent < Oracle Datablock<Tablespace

C.
Tablespace< Extent < Segment < Oracle Datablock

D.
Data File <Tablespace< Segment < Extent < Oracle Datablock

Explanation:
http://www.dummies.com/how-to/content/basics-of-logical-structures-in-oracle-12c.html