Step 1: Defining Internal Communication:
The query requires identification of characteristics defining internal communication. Internal communication refers to the exchange of information and ideas within an organization, distinct from external communication which involves outside parties.
Step 2: Detailed Analysis:
Each statement is examined:
(A) Employer-employee interaction within the same organization: This represents downward or upward communication, a fundamental aspect of internal communication.
(B) Interaction between employees of the same department and organization: This constitutes peer-to-peer or horizontal communication within a team or department, a definitive example of internal communication.
(C) Interaction among employees of the same organization but from different departments: This is cross-functional or diagonal communication, crucial for organizational collaboration and coordination, and is also classified as internal communication.
(D) Interaction between employees of different organizations: This is, by definition, external communication, involving exchanges with entities outside one's own company (e.g., clients, vendors, partners).
Step 3: Conclusion:
Statements (A), (B), and (C) all describe communication occurring *within* the confines of a single organization. Statement (D) describes communication that extends beyond these boundaries. Consequently, the defining features of internal communication are represented by (A), (B), and (C).