The correct answer is: A. Reliability
Reliability is the probability that a system will perform its required functions under stated conditions for a specified period of time. It is a measure of the system’s ability to avoid failures.
Crucial robustness is not a term that is commonly used in the context of reliability. It is possible that the author of the question meant to say “critical robustness”, which is a measure of the system’s ability to continue to function correctly in the event of a failure.
Feasibility is the ability to be done or carried out successfully. It is
not a measure of the system’s reliability.Therefore, the correct answer is A. Reliability.