The extent to which a software performs its intended functions without…

Answer: Reliability

Explanation: Reliability is the degree to which software performs its intended functions without failures over a specified period of time. It emphasizes continuous, failure-free operation (for example, uptime or mean time between failures).

• Why not robustness: Robustness describes the ability to tolerate invalid inputs or unexpected conditions without crashing, not the long-term, failure-free operation implied here.

• Why not correctness: Correctness means producing outputs that conform to the specification; it is about being functionally right, but does not capture continuous operation without failures.

• Why not accuracy: Accuracy refers to how close results are to true values, which is different from the concept of failure-free operation.

Short example: A reliable web service runs continuously without crashes for long periods (high reliability). A correct algorithm gives correct outputs when it runs (correctness), but it could still crash sometimes and so may not be reliable.