Question

efficient. then, in 1792, the newly - formed united states government officially established the postal service as a federal department. building on franklins progress, the department introduced additional reforms to ensure privacy and security in mail delivery. in addition, stealing mail was declared a federal crime, giving people greater confidence in their ability to exchange information safely and securely. much of this was left to the newly appointed postmaster general timothy pickering to enforce. before the war, it was a common occurrence for postal officials to open letters for surveillance purposes. one major advancement was to prevent postal officials from opening mail unless it could not be delivered. historians contend that many of these advancements were vital to americas early freedom of the press.

Explanation:

The text discusses the establishment of the US Postal Service in 1792 and reforms for mail - privacy and security. The blank needs a statement about a reform. The option "One major advancement was to prevent postal officials from opening mail unless it could not be delivered." best fits as it directly relates to the privacy and security reforms mentioned.

Answer:

One major advancement was to prevent postal officials from opening mail unless it could not be delivered.