The statement that best explains the reasons for the progression in information delivery is: The relay of information became more reliable as digital technology was used.
This is because advancements in technology over the years, from the Pony Express to US Postal Mail, and then to the fax machine and digital submissions, have generally made the process of delivering information faster and more efficient, as well as improving accuracy and reducing the risk of loss or damage. Digital technology has allowed for instant communication and better storage methods, which have collectively enhanced the reliability of information relay.