Taxonomy based on determination of genetic relationships is

All the orders together constitute which of the following?

In the given taxonomic sequence,what could $A, B$,and $C$ be?

The International Code of Botanical Nomenclature $(ICBN)$ has provided a code for the classification of plants. Provide the hierarchy of units of classification that botanists follow while classifying plants and mention the different 'suffixes' used for these units.

Which of the following is a class?

Assertion $(A)$: Maize is included in the class Monocotyledonae.
Reason $(R)$: This class does not contain any orders.