The correct answer is: A. system up time.
System up time is the percentage of time that a system is available for use. It is calculated by dividing the total number of hours that the system is available by the total number of hours that it is supposed to be available. A system with a high system up time is considered to be reliable and dependable.
System scalability is the ability of a system to handle increased demand without experiencing a decrease in performance. A scalable system can be easily expanded to meet the needs of a growing user base.
System availability is the probability that a system will be available for use at a given time. A system with a high system availability is considered to be reliable and dependable.
System efficiency is the ratio of the output of a system to the input of a system. A system with a high system efficiency is considered to be effective and productive.