In modular design, 'minimal coupling' means?

• A. Modules should depend on explicit interfaces and have limited knowledge of other modules.
• B. Modules should depend on each other's internal implementation details.
• C. Modules should share a single global variable space.
• D. Modules should be completely independent with no communication.

Answer: (A)

Minimal coupling means modules interact through stable, explicit interfaces and keep their internal workings hidden; each module relies only on what the interface exposes, not on the other module’s implementation details. This makes changes in one module less likely to ripple into others, and it supports swapping, testing with mocks, and reusing components.

That’s exactly what the option describing dependence on explicit interfaces with limited knowledge covers. It contrasts with depending on internal implementation details, which ties modules too closely together and makes changes risky. Sharing a global variable space creates hidden, pervasive connections that increase coupling and reduce maintainability. And expecting complete independence with no communication isn’t practical, since some coordination via defined interfaces is necessary for modules to work together.