Airspace:
A
B
C
D
E
G
From high to low altitude and also from high to low class of Airspace.
So you can have a Class D airport (partially) underneath a Class C but it won’t extend into it.
You can have a Class C airport (partially) underneath a Class B but it won’t extend into it.
So the higher Airspace overrules if you will.
Example is Tampa Class B