I really don’t know how to solve this...

How do I get the Chemclass which contains the largest number of antibiotics ?

relations given:
Antibiotic (AntibioticID, Name, SubclassID)
Subclass (SubclassID, Name, ChemclassID)
probably not needed, but given: Chemclass(ChemclassID, Name)

Many thanks in advance for any suggestion !