The main reason governments address public problems through policy is
A. to ensure that citizens' needs are met and protected.
B. to maintain strict control of the nation's economy and industries.
C. to control the economic safety of producers.
D. to protect the nation's level of productivity.

the answer is migration

i am sure the answer is d

answer: the time zones used to be whatever the local authority wanted them to be. one town might have 6am whenever the sun came up and another town had 6am 10 minutes later.  

the trains had a hard time when their orders said to be at a certain point at 6am.  

6am, but who's 6am.  

the railroads got together and set the time zones more or less along the longitude lines across the country.

explanation: