Solution

Correct Answer: (ii) system fault

Explanation

As per IEEE definitions (also Pressman/Sommerville):

• Human Error / Mistake - Human action that produces an incorrect result
• Fault / Defect / Bug - Characteristic / Anomaly in the software (e.g., wrong code, missing logic) that can lead to an error. It is a static condition.
• Error - Human-observable incorrect internal state (failure may not yet have occurred)
• Failure - Observable deviation from required behavior when system no longer performs required function

Chain: Mistake → Fault → Error → Failure

Hence a characteristic of the system that can lead to a system error is a Fault.

Why others incorrect:

• (i) Human error is the cause of fault, not a characteristic of the system itself
• (iii) Error is the result of fault, not the fault itself
• (iv) Failure is the final observable consequence after error propagates

Answer: (ii) system fault