Final answer:
Schein identifies 'Common purpose' as the unifying organizational feature in a bureaucracy, while 'Coercion to join' is not a characteristic of bureaucracies.
Step-by-step explanation:
According to Schein, the organizational feature that unifies employees or members and gives everyone an understanding of the organization's reason for being is C) Common purpose. This element is essential for aligning the efforts of all members, ensuring that everyone is working towards the same goals and objectives. On the other hand, referring to the characteristics of bureaucracies, the option that is not a characteristic is A) Coercion to join, since bureaucracies typically feature a hierarchy of authority, a clear division of labor, and explicit rules, but do not require coercion for membership.