Standards and interoperability: having compatibility and commonality across and between different vendors’ equipment is called:

Introduction / Context:
In technology ecosystems, products from different vendors must interoperate to reduce lock-in and integration costs. Achieving compatibility across hardware and software requires agreed-upon specifications and conformance testing so that components work together predictably.

Given Data / Assumptions:

• The question asks for the term describing compatibility/commonality across vendors.
• We focus on shared specifications, interfaces, and behaviors.
• Other terms like integration or networking describe activities or architectures, not the underlying harmonization process.

Concept / Approach:
Standardization is the process of developing and adopting technical standards—protocols, file formats, mechanical dimensions, signaling levels, safety rules—so that independently developed components can interoperate. This promotes economies of scale, simplifies maintenance, and enables a healthy multi-vendor marketplace.

Step-by-Step Solution:
Identify the requirement: cross-vendor compatibility and commonality.Associate that with standards creation and adoption.Select “Standardization.”

Verification / Alternative check:
Examples include IEEE, ISO, IEC, and W3C standards that enable plug-and-play across vendors.

Why Other Options Are Wrong:
Registration (A) is enrollment or alignment, not broad compatibility. Integration (C) is a project activity combining parts, often bespoke. Networking (D) is a domain, not the harmonization mechanism. E is invalid because the correct term exists.

Common Pitfalls:
Confusing de facto compatibility with formal standardization; de jure standards provide clearer, testable conformance.

Final Answer:
Standardization.