In industrial control, one key advantage of a programmable controller (PLC) over hard-wired relay logic is that it:

Introduction / Context:Programmable controllers replaced many banks of electromechanical relays by offering software-configurable logic with solid-state reliability. Their modular I/O, diagnostics, and ease of modification improve uptime and reduce maintenance in industrial environments.

Given Data / Assumptions:

• Electromechanical relays wear over time due to contact arcing and mechanical movement.
• PLCs use solid-state electronics with far fewer wear-out mechanisms.
• Training and documentation make PLC logic accessible; unreliability is not due to lack of moving parts.

Concept / Approach:Reliability increases when you remove mechanical wear points. PLCs consolidate logic in software, provide error detection, and support rapid reconfiguration without rewiring. Mean time between failures is typically higher than relay banks, and change management becomes a software process.

Step-by-Step Solution:Compare relay contacts (mechanical wear) vs. PLC solid-state switching.Assess maintainability: PLCs allow edits without rewiring, reducing downtime.Choose the option emphasizing reliable long life versus relay logic.

Verification / Alternative check:Industry case studies consistently report reduced failure rates and maintenance after migrating to PLCs.

Why Other Options Are Wrong:B exaggerates difficulty; ladder logic is designed to be readable. C is backward—solid-state often increases reliability.

Common Pitfalls:Ignoring environmental specs; even solid-state systems need proper enclosures, grounding, and surge protection.

Final Answer:Has a reliable long life compared to relay logic.