A non-obligate category introduced between class and division is

The correct option is C Superclass
Between the Class and Division category, superclass is introduced which refers to the assemblage of similar classes. For example, in the classification of fishes, after the Phylum (or division) pisces, superclass is introduced Agnatha is introduced which refers to all the jawless fishes. Thereafter, classes start.

A. Tribe is introduced between Family and Genus and it refers to a group of genera.

B. Subclass is introduced between Class and Order.

C. Superclass is introduced between Division (or phylum) and Class.

D. Taxon is any group in the whole hierarchy of classification.

Hence, the correct answer is 'Superclass'