May Has Experience Developing Applications Using XSLT 1

May has experience developing applications using XSLT 1.0, and would like to take advantage of some of the added features of XSLT 2.0 in developing a new application. She comes to you for help implementing some of these new features.
-May is familiar with working with a wide variety of node types in XPath 1.0, but is confused when changing to the atomic values used in XPath 2.0. You explain to her that each atomic value has a data type that describes the kind of data it contains, and this data type is specified using the _____ attribute.

A) select
B) use
C) type
D) as