How can administrator meet this requirement?

An Administrator is preparing to deploy change set into the production environment. Until the deployment is complete, only user with System Administrator profile should be allowed to access data in the production system. When any other user attempts to log in, a maintenance notice should be displayed instead.

How can administrator meet this requirement?
A . Assign all other users a custom profile with read access to all objects revoked and add a custom home page message
B . Add login hours to all profiles except System Administrator and set the custom maintenance message
C . Add Individual IP range to all profiles except System Administrator and add a custom home page message
D . Activate Planned maintenance window feature and set the custom maintenance message

Answer: A