44.EasyBuy.com is an online retailer that sells books and magazines at half-price. They recently found out that due to the huge amounts of traffic that Web site receives, most users are unable to access the site when they want to and, when they do, the pages load very slowly. This is driving customers away to other rival online bookstores. This is an example of which of the following infrastructure-centric metrics?

A.Abandon rate
B.System availability
C.Error rate
D.Time service factor