What Is the General Classification Used to Categorize Leukocytes

What is the general classification used to categorize leukocytes?

A) It depends on the age of the cell, as all agranulocytes start off as a granulocyte and later change their function and structure over the life of the cell.
B) whether or not leukocytes have granules in their cytoplasm that are visible when stained and then viewed by light microscopy
C) whether they function as part of the innate or adaptive immune system
D) whether or not the cells contain a nucleus
E) whether the cells originate from primary or secondary lymphoid tissues