What is a valid way of referencing the global cc_api_CartExtentsion apex class via subscriber code?

What is a valid way of referencing the global cc_api_CartExtentsion apex class via subscriber code?
A . ccrz__cc_api_CartExtension
B . c__cc_api_CartExtension
C . cloudcraze.cc_api_CartExtension
D . ccrz.cc_api_CartExtension

Answer: D

Explanation:

A valid way of referencing the global cc_api_CartExtension apex class via subscriber code is to use ccrz.cc_api_CartExtension. This is the name of the class that is defined in the cloudcraze managed package. The class is global, so it can be accessed by subscriber code. The other options are either invalid or incorrect.

Reference: B2B Commerce and D2C Commerce Developer Guide, API Classes