What are two reasons that would prevent a user from being deactivated?

An administrator at Cloud Kicks wants to deactivate a User who has left the company.

What are two reasons that would prevent a user from being deactivated? Choose 2 answers
A . The use is part of a territory hierarchy.
B . The User is in a Custom hierarchy field.
C . The User is assigned in workflow email alert.
D . The User is the highest role in the role hierarchy

Answer: A,C