Answer:
d. availability
Step-by-step explanation:
Availability can be defined as the quality of a thing, system, business, service or person to be available at all times (24 hours a day) to the group of people that uses it.
This ultimately implies that, availability is a state of being consistently accessible to the end users on daily basis without any downtime or failure.
Hence, a network designed for availability is one that delivers consistent reliable performance 24 hours a day to the end users.