well A and C both happened in the 80's but B was in the 70's.. So someone made the choices unreliable. But the best answer would be
<u>D.) All of the above.</u>
Umm, can you give us something to go on? like some options?
Answer:
It increased national unity by reducing sectional differences. It boosted the speed of cross-country mail delivery.
Explanation:
hope this helps have a nice day :)
