How are version related upgrades passed on to subscriber API extensions/overrides?

How are version related upgrades passed on to subscriber API extensions/overrides?
A . APIs callback with specific versions specified; the user must know which version number to use.
B . Copy and paste of specific code is "built-in"
C . Extensions and overridden APIs don’t support-related upgrades.
D . The "delegate" allows inherited method calls access to the most recently specified service version

View Answer

Answer: D