A. Open System Interface
B. Out System Interface
C. Open System Interconnection
D. Out System Interconnection.

Solution

C. Open System Interconnection

Explanation

The Open Systems Interconnection model (OSI Model) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard of their underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard protocols. The model partitions a communication system into abstraction layers. The original version of the model defined seven layers.