Choose the word or phrase - a, b, c or d - that best fits the blank space in the following passage.

A major revolution for the automated office is electronic mail. The customary (1) _______ system requires message written on paper to be (2) _______ physically from one location to another. With electronic mail, messages are converted (3) _____ electronic signals, transmitted (4) _____ in the world, and then changed back into the original written form, all in several seconds and minutes at (5) ______.

Through the use of video screens in company offices, a single (6) ____ can be transmitted to hundreds of people in dozens of branch offices at the same time. Thus, electronic mail, along with (7) ______, can be an important asset in teleconferences. Furthermore, the use of electric mail in the form of a 'mailbox' (8) ______ to a telephone is also of great value. Since in offices many telephone (9) ______ go uncompleted on the first attempt, with electronic mail, two-way conversion is not essential, so it (10) ______ telephone use and saves time.

(1) __________

• A. 
  post
• B. 
  postal
• C. 
  postage
• D. 
  posting